Kidd-Palmer Treasure Maps SOLVED by Oliver D. Smith

[Bocaj]

Overlay with RI's center cliff and death valley moved together to the same place on the Key map. the circle covers the "skull" exactly! the 'Y' type of drawing with the left '\' pointing towards the cave.

 

[Bocaj]

another discovery!
Wilkins was right: the Coral Map shows Death Valley exactly where he draw it on that postcard. WHen I enhanced that photo I didn't notice it. Hard to see but its there. It was just not copied onto the copies we use now.

Still it doesn't say "Death Valley" - where did Wilkins got that name from?

 

[Cryptid1990]

View attachment 2257310

If that is a skull it is of an alien or an Atlantian. Maybe Yoda's. Well I think its a clear case of pareidolia. The "Face" on Mars has more similarities with a skull than this one. And there is no indication of a valley (some strokes on both sides or even just one).

It is suspicious.

What the above could represent is a description of the RI's Death Valley. I think I remember something about a circle - have to read that part again.

Also the position of the 32/1 confirms my idea that the Palmer maps are earlier sketches were the author still positions the other entry to the goldmine in the lower middle of the island. I think later he moved the mine and the cave into that inner cliff he created as a better base for the final confrontation. I can see him over and over redrawing the island in the end with many sketches laying around. They had now value to him other than memories. To good to throw away - just right to be stuffed into some old furniture.

I should have clarified, if you rotate the oval ('skull') you do see a face:

But this could indeed be pareidolia.

 

[Cryptid1990]

another discovery!
Wilkins was right: the Coral Map shows Death Valley exactly where he draw it on that postcard. WHen I enhanced that photo I didn't notice it. Hard to see but its there. It was just not copied onto the copies we use now.

Still it doesn't say "Death Valley" - where did Wilkins got that name from?

Unfortunately I cannot see it right now since it is difficult to see (I will try again) but can you enhance the following?

Watch from 2:12-2:14 minutes.


Then take a screenshot and rotate the map (since it is upside down in the video).

This is the original Skeleton Map in 1949.

See my post from another thread for a photograph in The Boston Globe (8 January 1950):

 

[Cryptid1990]

I reread Wilkins' book (1935 [US edition, 1937]) and some of his articles (1936, 1940) and he makes it clear in all of them that "Death Valley" was not on the Coral Island Map but only the Skeleton Map. His description of the Coral Island Map (Wilkins, 1936):

His description of the Skeleton Island Map (Wilkins, 1936):

Note that in this article he does not claim "Death Valley" was annotated as a place name on the map but was written on the border margin of the Skeleton Map as a clue alongside "triangles" and "stakes in a lake". Some of the writing on the margin of the map is illegible and Wilkins was therefore guessing. There does appear to be the word "tri" (= triangle?) but "stakes in a lake" is almost certainly incorrect:

Wilkins visited Palmer in Eastbourne at least two times (Summer 1932, 1933) and saw the maps, but by the time he wrote his book and articles he had to rely on his memory since Palmer denied him permission to make reproductions for his 1935 book.

Wilkins (1940):

Wilkins in this article similarly notes that there is a "reference to an eerie Death Valley" on the margin of the Skeleton Map. Despite some of the text is illegible, there are not the words "Death Valley"? So a straightforward possibility is that Wilkins made a mistake. Anyway, we now know that Wilkins was not saying that "Death Valley" was on the map as an annotated place (like Smuggler's Cove) but clue on the margin.

Edit: in Wilkins' (1942) article he in fact suggests the opposite; "Death Valley" was an annotated place. So who really knows. The relevant text in his article reads as follows: "[I compromised by giving a chart with all the details that Mr. Palmer] permitted. I changed the outline of the shores of the coral and turtle island, but gave the hills with caches, and a 'Death Valley,' actually in Kidd's charts. I also inverted the compass points, placing north where south usually is."

 

[Bocaj]

I reread Wilkins' book (1935 [US edition, 1937]) and some of his articles (1936, 1940) and he makes it clear in all of them that "Death Valley" was not on the Coral Island Map but only the Skeleton Map. His description of the Coral Island Map (Wilkins, 1936):

View attachment 2257373
His description of the Skeleton Island Map (Wilkins, 1936):

View attachment 2257372
Note that in this article he does not claim "Death Valley" was annotated as a place name on the map but was written on the border margin of the Skeleton Map as a clue alongside "triangles" and "stakes in a lake". Some of the writing on the margin of the map is illegible and Wilkins was therefore guessing. There does appear to be the word "tri" (= triangle?) but "stakes in a lake" is almost certainly incorrect:

View attachment 2257374
View attachment 2257375
Wilkins visited Palmer in Eastbourne at least two times (Summer 1932, 1933) and saw the maps, but by the time he wrote his book and articles he had to rely on his memory since Palmer denied him permission to make reproductions for his 1935 book.

Wilkins (1940):

View attachment 2257383

Wilkins in this article similarly notes that there is a "reference to an eerie Death Valley" on the margin of the Skeleton Map. Despite some of the text is illegible, there are not the words "Death Valley"? So a straightforward possibility is that Wilkins made a mistake. Anyway, we now know that Wilkins was not saying that "Death Valley" was on the map as an annotated place (like Smuggler's Cove) but clue on the margin.

Edit: in Wilkins' (1942) article he in fact suggests the opposite; "Death Valley" was an annotated place. So who really knows. The relevant text in his article reads as follows: "[I compromised by giving a chart with all the details that Mr. Palmer] permitted. I changed the outline of the shores of the coral and turtle island, but gave the hills with caches, and a 'Death Valley,' actually in Kidd's charts. I also inverted the compass points, placing north where south usually is."

this is as much as I can get out of a low-res frame of that small clip

If you look long enough you will see those two strokes '\\' in the enhanced map. In any case it is Coral Map not the Key map that he refers to in that postcard. This Death Valley is quite certainly written nowhere on any map. It stay's a an unresolved issue.

Also is the other post I showed that the skull is without doubt the circle in RI's Death Valley drawing. I means it is no skull and was never intended to be one.

In any case the Palmer Maps never "needed" a Death Valley. It is an artifact from the RI story. The margin of the Key Map is an addition to the original RI sketch merging the details taken from the "Avery the Pirate" letter into the map. That's why it has that strange wide margin as the copy of the original sketch didn't allow for the additional text. The inner frame is just the the margin of the original sketch!

All this supports my idea that the maps are nothing but sketches for that book copied on old vellum with some additions to associate them with pirate treasure and Kidd.

 

[Randawg72]

Congrats Mr. Smith. You followed a longshot theory from a forgotten book and presented a compelling case.
However this discovery raises some questions. At least one example of 'Rainbow Island' was clearly reprinted much later than the copyright date. And suspiciously some of the reprints were not formally dated at all (As per posts #23, #67, and my example #28). The earliest copy shown so far has a copyright date of 1917.
I wonder if this map could have been known and published sometime before Palmer had acquired it? As Bocaj mentioned, the Death Valley reference is a well known H. T. Wilkins creation on maps that he drew for his 1935 book. And if it was Wilkins that copied this detail from Tracy's book, then why not the island outline as well? While the actual Kidd/Palmer charts were not officially made public until 1949, they were shown to at least one author (Wilkins), and circulated to map experts soon after their discovery.
Which makes more sense. For a fiction writer to copy a treasure map to illustrate his book, or for a fraudster to copy a published map to perpetrate a hoax? Why risk being caught when it would have been so easy to draw his own?
I'm not ready to reveal my findings just yet. So I'll be filing this under "SDLR".

(Per Cryptid1990: "The map does not appear in the US version or reprints, only UK version and reprints (up to the late 1940s").
Since 1909 the US had rigid copyright laws requiring registration and accurate printing dates which Britain did not adopt until the 1950's.
Strong support that the map was likely added by the publisher.


https://www.copyright.gov/history/1909act.pdf ©

 

[Carl-NC]

The earliest copy shown so far has a copyright date of 1917.

1904, actually.

 

[Bocaj]

Which makes more sense. For a fiction writer to copy a treasure map to illustrate his book, or for a fraudster to copy a published map to perpetrate a hoax? Why risk being caught when it would have been so easy to draw his own?

Which is a quite valid argument but it also does support my theory that those maps are earlier sketches done while developing the RI (or some previous unpublished) story by Tracy (or Shiel). Which means the hoaxer didn't even know it was printed in a book before. He (Cutler) just got them together with some old furniture (Shiel had to sell his) and made the best use of them by copying them onto some old will adding a bit of text to associate them with Kidd. Not much effort and he wasn't aware of the risk to be discovered as he didn't know of that book.

 

[Cryptid1990]

another discovery!
Wilkins was right: the Coral Map shows Death Valley exactly where he draw it on that postcard. WHen I enhanced that photo I didn't notice it. Hard to see but its there. It was just not copied onto the copies we use now.

I found a much clearer photograph of the Coral Island Map (see Kidd: The Search For His Treasure [1996] p. 12). There is no Death Valley on it. Based on this photograph and the fact Wilkins was adamant that 'Death Valley' was only on the Skeleton Map (in most his articles he said it was referenced as a clue on the margin but in his 1935 book and 1942 article, he suggested it was drawn on the map), I think we can rule out the Coral Island Map as having Death Valley on it.

Still it doesn't say "Death Valley" - where did Wilkins got that name from?

The answer will likely be found in Wilkins' files (unpublished papers) or correspondence with Palmer. Unfortunately, the people who hold this information are doing nothing with it, selfishly keeping it for themselves and/or are on a false trial. I have repeatedly asked for everything to be published in the public domain. The reason the people who own Wilkins' files have not done this is they wrongly believe there is a treasure on Oak Island and clues on the Coral Island/Skeleton Map relate to Oak Island. Total nonsense. There are no clues to instructions to any real treasure in the Coral Island/Skeleton Maps, not on Oak Island, or anywhere else for that matter (we can also dismiss irrational claims made on this forum of a treasure on the Pinaki atoll) - as I explained earlier in this thread - it is obvious that the instructions on the Skeleton Map were based on the fictional RI map which has a ruler for measurements in yards. You have to use the Skeleton Map instructions on the RI map and the instructions lead you to the fictional cave with "gold-bearing rock". I hope one day the people (or person) who own Wilkins' unpublished papers and correspondence will come to their senses and realise since there is no real treasure - they have nothing to loose by putting everything in the public domain. The only question that remains unanswered is who the hoaxer was. I have managed to get closer to answering that question and found a lot more evidence since I have managed to gain access to certain documents in museums and archives, however, I will wait to publish it in an article given the recent incident here.

 

[Cryptid1990]

Congrats Mr. Smith. You followed a longshot theory from a forgotten book and presented a compelling case.
However this discovery raises some questions. At least one example of 'Rainbow Island' was clearly reprinted much later than the copyright date. And suspiciously some of the reprints were not formally dated at all (As per posts #23, #67, and my example #28). The earliest copy shown so far has a copyright date of 1917.

I now own reprints earlier than 1917 and they all contain the RI map. The earliest dated copy I own is 1912. Although I do not own a copy of the 1904 reprint [sixpenny paperback edition], I contacted a seller of the 1904 reprint published in The Collected Works of Louis Tracy (T. Sealey Clark; Ward, Lock & Co., Limited; F. V. White & Co., Limited; C. Arthur Pearson LTD; Digby, Long & Co 1904-07, London, 1904.) They sent me proof that the RI map appears in the 1904 reprint / Collected Works (see below [or here for photos]).

Prior to me creating this thread on 24 May 2026 when I first publicly posted and revealed the Kidd-Palmer maps were based on/copied from Louis Tracy's Rainbow Island [1903] novel (which contains the RI map), there were about thirty copies of Rainbow Island on various websites that list books for sale (excluding worthless modern 'print on demand'). However, immediately afterwards, someone (or a small group of people) began trying to frantically buy all the copies resulting in a bidding war. I mentioned this on 9 June 2026 and I had observed this happen days earlier. Frustratingly, the first edition (1903) of Rainbow Island was bought by someone else the same week from Shapero Books despite I had it in my 'basket' on Abebooks. The timing could hardly have been a coincidence and was bought by someone who read my thread and research, bought the scarce first edition, and has tried to now buy every reprint of the book with the RI map. I listed several reprints and editions of the book on 3 June 2026. I contacted about a dozen sellers over past few weeks who said they had sold the books that same week or the prior week after this thread was created.
Before my thread, there was no big interest in Rainbow Island and the thirty copies for sale had not been bought for many months or even years. The 1903 first edition was listed by Shapero Books in August 2025. So it is clear someone only bought the first edition and the reprints this month because of this thread I created. They were oblivious to RI before my research and this thread creation.

As I said, this is frustrating since the person who bought the first edition is not going to do anything useful with it and is probably on the complete wrong track in terms of uncovering the hoaxer nor understands how the clues on the Skeleton Map relate to the Rainbow Island map. Furthermore, the buyer has not scanned or uploaded a digital image of the map anywhere, nor added anything of value and is keeping it for themself. I would like to have seen if there are any differences in the 1903 map [first edition]. If I had bought the copy from Shapiro Books, I would have scanned and uploaded it here (like I did the reprints). All that said, since I realised early on what was happening, I bought approximately 18 of the ~30 Rainbow Island books. My collection now includes some rare editions and reprints, and numerous duplicates. As further proof of the so-called bidding wars, note that The Collected Works of Louis Tracy (1904-07, London, 1904.) has shot up in price to over £3,000. The seller has had multiple recent offers and considering my thread, book sellers are now increasing the prices of the few remaining copies of Rainbow Island.

I wonder if this map could have been known and published sometime before Palmer had acquired it? As Bocaj mentioned, the Death Valley reference is a well known H. T. Wilkins creation on maps that he drew for his 1935 book. And if it was Wilkins that copied this detail from Tracy's book, then why not the island outline as well? While the actual Kidd/Palmer charts were not officially made public until 1949, they were shown to at least one author (Wilkins), and circulated to map experts soon after their discovery.
Which makes more sense. For a fiction writer to copy a treasure map to illustrate his book, or for a fraudster to copy a published map to perpetrate a hoax? Why risk being caught when it would have been so easy to draw his own?
I'm not ready to reveal my findings just yet. So I'll be filing this under "SDLR".

(Per Cryptid1990: "The map does not appear in the US version or reprints, only UK version and reprints (up to the late 1940s").
Since 1909 the US had rigid copyright laws requiring registration and accurate printing dates which Britain did not adopt until the 1950's.
Strong support that the map was likely added by the publisher.


https://www.copyright.gov/history/1909act.pdf ©

The 1904 reprint has been verified as having the RI map (see above) and it is almost certainly appears in the 1903 first edition. In the 1920s, for unknown reasons, some minor changes were made, namely removing the name "Robert Jenks" (the protagonist in the novel) from underneath the map and a different font was used for some of the annotated place names.

The Kidd-Palmer maps were purchased by Hubert Palmer sometime between 1925-1934. Palmer showed the map from the Hardy Chest to Vice Admiral Sir Reginald Hall in Eastbourne. Hall served as the MP for Eastbourne between 1925 and 1929. Wilkins (1942) states Palmer met Hall in 1925, but in his other articles and 1935 book, states the visit took place in 1929 or 1930. Palmer in 1930 sent a letter to Charles Driscoll and Driscoll (1930) noted that Palmer said he came to acquire the Hardy Chest (and map inside) about three years earlier. Although not specific, this does suggest 1927, although 1925 cannot be ruled out. Wilkins (1935) noted Palmer bought the Skeleton Map in 1933 and this is confirmed by a letter Palmer wrote to Wilkins, although Howlett (1958) claimed 1934.

It is not even tenable to continue argue the Kidd-Palmer maps are authentic treasure maps and not a hoax. The RI map dates to 1903 ([1904 now verified]) so that is a gap of 22-24 years to when Palmer bought the Hardy Chest and map, or ~30 years to when Palmer acquired the Skeleton Map. The Kidd-Palmer maps have no verifiable provenance before Arthur Hill-Cutler sold the furniture pieces (with maps) to Hubert Palmer. Furthermore, as I explained in other threads, we know the person whoever drew the Kidd-Palmer maps was responsible (or at least involved) in forging dozens to hundreds of "Lord Nelson relics". What are the chances a forger/ hoaxer copying an authentic treasure map?

 

[Randawg72]

So this is what you accept as verified proof of an authentic print date?
(If this was meant as a joke, my apologies. And thank you for the belly laugh).
When you can produce some legitimate 'proof', I'm sure we'd all like to see it.

(Please note that as per post #107, I am suspicious of the authenticity of any and all British print dates).

 

[Cryptid1990]

View attachment 2257754
So this is what you accept as verified proof of an authentic print date?
(If this was meant as a joke, my apologies. And thank you for the belly laugh).
When you can produce some legitimate 'proof', I'm sure we'd all like to see it.

(Please note that as per post #107, I am suspicious of the authenticity of any and all British print dates).

A print date does not always need to be inside a book to know when it was published/printed. Only the first edition of Rainbow Island used red and black ink on the title page which is why we know the above title page is from the first edition (1903). There is also the fact that the physical copy with 1903 written in pencil was authenticated by an expert as a first edition by Shapero Rare Books who are an internationally renowned dealer in antiquarian and rare books. On top of this, the same copy has a previous owner's date on it: "John Howe Green Sept: 1904" so the book must have at least been that old. Face it, you have been thoroughly refuted. The RI map appears in the first edition (1903) and I already provided proof the earliest reprint (1904) contains the same map. I also uploaded a scan of a 1917 reprint with the map.

 

[Bocaj]

I would hope to get back on track here and not waste more words about who discovered the map first. I think it is clear to see for anyone!

The question you were looking into is who the hoaxer was. Looking forward to your answer.

 

[Cryptid1990]

I would hope to get back on track here and not waste more words about who discovered the map first. I think it is clear to see for anyone!

The question you were looking into is who the hoaxer was. Looking forward to your answer.

I will do a long post in the near future since I am waiting for something. However, right now I can point out the following:

• Louis Tracy prior to publication of his book in September 1903 would have discussed his manuscript during correspondence with the publisher of his book (Ward, Lock & Co.) and/or the artist the publisher commissioned to draw the map (Fred Pegram). A possibility is that Tracy himself made a rough sketch of the RI map and Pegram used this sketch. I therefore began looking into the archive of the publisher that would have stored letters between Tracy and the publisher (Ward, Lock & Co.) and/or Pegram. However, this turned out to be a dead end since the archive at their headquarters (Warwick House in Salisbury Square, London) was destroyed during WW2.
• All archival documents (file copies of publications and author correspondence) were destroyed by German bombing on 29 December 1940. This explains why Ward, Lock & Company's offices (including archive) moved to 6 Chancery Lane, London in 1946. The only archival copies of publications and author correspondence from Ward, Lock & Co., therefore date post-1940 (after the bombing).
• Tracy died in 1928 and he published his book in 1903 so the post-1940 archive by Ward, Lock & Co., is of no relevance.
• Another possibility, is an archive somewhere of Fred Pegram's drawings, contains information about the map. Unfortunately, I could not find anything after searching and also contacting the British Museum. The V&A South Kensington Database lists a collection of Pegram’s original drawings but not the RI map (nor any of his illustrations in Rainbow Island). Another dead end.

Based on the above, I have managed though to determine when the final reprints of the RI map appeared. Rainbow Island was reprinted in 1946 when Ward, Lock & Company moved their HQ (including archive) to 6 Chancery Lane, London. Between 1946 and 1953 the final reprints appeared. In 1954, Ward, Lock & Company moved their headquarters to Piccadilly and they no longer reprinted Rainbow Island.

In 1943, Leslie Lock, the last remaining son of co-partner George Lock was the head of the business, until joined on staff by Colonel Eric Shipton, a decorated veteran of WWI. The company took up residence for a few short years at 6 Chancery Lane, London, after the bombing of their Warwick house, until a more permanent residence [1954] was made at 143 Piccadilly. However, in 1964, the business split in two, creating Ward Lock Educational Ltd, which was bought by Cassell Publishing in 1989. By the early 90’s, Cassell was acquired by the currently existing company, Orion Publishing.

Ward, Lock, & Co. · The Art of Reprinting · Wide, Wide World Digital Edition

<i>The Wide, Wide World Digital Edition</i> maps transatlantic publication networks via the development of a digital edition of Susan Warner’s 1851 female Bildungsroman <i>The Wide, Wide World</i>. Warner’s American novel was a transatlantic success that was steadily reprinted for the next one...

widewideworlddigitaledition.siue.edu

Useful timeline: https://wlrg.z33.web.core.windows.net/page/aboutWLevents.html
(Source: Adventure In Publishing, The House Of Ward Lock, 1854-1954 by Edward Liveing [1954])

Amazingly, I managed to purchase the publisher file copy of a Rainbow Island reprint (1946-1953) that was formerly stored at Ward, Lock & Company's archive at 6 Chancery Lane, London. The reprint has the address on the inside book cover:

There is also a sticker that mentions the file copy:

The book cover:

As the publisher file copy this is one of a kind. I am pleased to own it.

 

[Bocaj]

It is also a possibility he recycled an unpublished story by himself or maybe Shiel. I think it was quite common and the IP issue wasn't as strict as today.

Someone here mentioned that the full map was only published in Britain because the US had stricter copyright laws. It is possible he took the map from some other source like mentioned above. I think the hoaxer didn't copy it from the RI version. Would have been stupid as this book was even made as a movie. Who would take that risk instead of creating a new map? Using some unpublished manuscript would look much safer.

 

[Cryptid1990]

I have now published an article in The Skeptic:

https://www.skeptic.org.uk/2026/07/the-kidd-palmer-maps-conclusively-proven-to-be-a-hoax-lifted-directly-from-fiction/

Smith, Oliver D. "The Kidd-Palmer Maps conclusively proven to be a hoax lifted directly from fiction", The Skeptic (1 July 2026)

I am still working on a lengthy manuscript for a peer-reviewed journal. However, I am also now writing a manuscript to submit to Skeptical Inquirer and if it is accepted it should be published in the next few months. Completely unrelated but I managed to come up with a plausible solution to the Oak Island/'Money pit' mystery and hopefully will have that article published next month in The Skeptic.

 

[Bocaj]

I found something interesting rg Shiel in Wikipedia:

He may have met Markino through Arthur Ransome who dedicated Bohemia in London (1907) to Shiel and used him as the model for the chapter on "The Novelist."

Guess what?
Ransome:

He is best known for writing and illustrating the Swallows and Amazons series of children's books about the school-holiday adventures of children

Also Ransome studied Stevenson...

 

[Randawg72]

Let's take an objective look at the original (canister lid) island drawing that appeared in the first edition of Tracy's
"The Wings of the Morning" published in New York, September 1903.

The island has a banana shape with a wonky north south inclination.
It also has dots that may (or may not) represent a north to south rift or canyon, and an 'X'
marking the spot of a presumed treasure. All synonymous with some of the Kidd/Palmer maps.
The most interesting similarity to me is the 9.16 N latitude reference.
What this drawing does not have is a northern rocky reef with a lagoon, any turtle references, an anchorage point, nor any mention of sand, coral, wrecks, or southern reefs.
Details are missing like the China Sea, and smuggler's cove references, but they are mentioned in the story.
I acknowledge that these details were on the "Rainbow island" map which would appear later in some British prints.

While the similarities of the canister map to the Skeleton map could easily be dismissed as
coincidence. For the (Britain added) "Rainbow Island" map to match the Skeleton map
so closely, (including the 9.16 N) completely by accident would be very unlikely.
I still believe in my solution. A lot of which was derived from the Coral Island map.
But I wonder why if the "R.I." map was actually published in 1917 in a popular novel, how did nobody notice the resemblance to Kidd's Skeleton map for nearly 95 years? Why are the RI landmarks so different from the Kidd charts? Why all the undated and mis-dated reprints? And why the misinterpreted longitude?, And is it possible that the Skeleton map was previously known, or that alternate copies of it exist?
This is a lot to absorb.

 

[Cryptid1990]

Let's take an objective look at the original (canister lid) island drawing that appeared in the first edition of Tracy's
"The Wings of the Morning" published in New York, September 1903.
View attachment 2259759
The island has a banana shape with a wonky north south inclination.
It also has dots that may (or may not) represent a north to south rift or canyon, and an 'X'
marking the spot of a presumed treasure. All synonymous with some of the Kidd/Palmer maps.
The most interesting similarity to me is the 9.16 N latitude reference.
What this drawing does not have is a northern rocky reef with a lagoon, any turtle references, an anchorage point, nor any mention of sand, coral, wrecks, or southern reefs.
Details are missing like the China Sea, and smuggler's cove references, but they are mentioned in the story.
I acknowledge that these details were on the "Rainbow island" map which would appear later in some British prints.

In the story, it is a crude drawing on a tin can by a pen knife so we should not expect to see much detail (like the RI map). Louis Tracy's fictional Rainbow Island is located in the southern China Sea so this explains why the geographical coordinates (9.16 N, 113.80 E) match that region of water, although since the island is imaginary the coordinates do not point to a real island. The hoaxer who drew the Skeleton Map copied verbatim 9.16 N from the RI map but changed the longitude (partly by rearranging the digits 1 and 3) to 431.30 E or 31.30 E.

While the similarities of the canister map to the Skeleton map could easily be dismissed as
coincidence. For the (Britain added) "Rainbow Island" map to match the Skeleton map
so closely, (including the 9.16 N) completely by accident would be very unlikely.
I still believe in my solution. A lot of which was derived from the Coral Island map.
But I wonder why if the "R.I." map was actually published in 1917 in a popular novel, how did nobody notice the resemblance to Kidd's Skeleton map for nearly 95 years? Why are the RI landmarks so different from the Kidd charts? Why all the undated and mis-dated reprints? And why the misinterpreted longitude?, And is it possible that the Skeleton map was previously known, or that alternate copies of it exist?
This is a lot to absorb.

As I mentioned in previous comments, the RI map never appeared under the US title The Wings of the Morning, only under the UK title Rainbow Island (meaning no one who read WotM would have come across the RI map, although the tin canister map appears in both). Far fewer copies under the UK title were printed and sold than the US title. The book is more widely known under the WotM title. In the early 20th century, the scale of the US book publishing market often eclipsed that of the UK and it seems 'Wings of the Morning' was a more attractive title to readers than Rainbow Island, perhaps because of its biblical connotations. An American silent drama film Wings of the Morning (1919) was based on WotM and the book was published in Iceland in 1959 under the title Á vængjum morgunroðans (On the Wings of the Morning Sun) as a variant of WotM. If you search for WotM today on websites that sell second-hand books you find hundreds to thousands of copies. In contrast, there are virtually none listed for sale under the Rainbow Island title and the thirty copies that were previously listed have almost all sold (excluding one) and they are much more scarce than WotM. There has been a recent frenzy to buy these in response to this forum thread. I bought about 20/30 of the copies including most recently a 1910 reprint by London: The Romance Book Club. I managed to find out who bought two of the copies from a book seller in France; the buyer contacted me by email and admitted they bought the copies after reading this thread. I do not though know who bought the first edition from Shapero Books.

It is reasonable to infer that WotM printed and sold tens of thousands of copies but RI a 4-digit number, probably towards the lower end. Many of those have since been destroyed; Ward, Lock & Company's headquarters (including its archive with publisher copies of the book) was bombed during WW2. The RI map was not digitised anywhere online until I scanned and uploaded it from a reprint on 4 June 2026 and it has to also be taken into account that a reproduction of the Skeleton Island map did not appear in a book (The Money Pit Mystery) until 1972 by Rupert Furneaux. Prior to that year, only a handful of people had personally seen or examined the Kidd-Palmer maps* and Harold T. Wilkins' [1935] drawings did not closely resemble the maps since Hubert Palmer refused him permission to copy them (*with exception that the Skeleton Island map was briefly shown by Dick in a film clip titled "Pirates Treasure" (1949) but this was a cinema newsreel segment and the map was presented by Dick upside down and much of the island depicted on the map is poorly visible). By the 1970s, Rainbow Island was no longer reprinted (the last reprint by Ward, Lock & Co., was between 1946 and 1953).

Finally, individuals who owned the original maps or copies of the maps, incorrectly believed the maps were authentic and drawn or owned by Captain Kidd. This included Palmer and Elizabeth Dick, as well as Howlett (1958) and Furneaux (1972). These people did little to no research on the maps nor tried to verify their provenance; they naively accepted at face-value or through wishful-thinking - they were authentic pirate treasure maps, despite overwhelming evidence to the contrary (they are a hoax). So basically, the people who had access to the original maps and/or copies of them, were always on the wrong track. The probability that someone who believed the Skeleton Island map is authentic would stumble across the RI map (which is fairly obscure since Rainbow Island copies are scarce) by sheer accident, is remarkably small. In contrast, my research put me on the right track to begin with since it was obvious based on the evidence (I detailed elsewhere) that the Kidd-Palmer maps are a hoax and nothing to do with Captain Kidd. I was specifically therefore searching for a fictional map that the hoaxer copied or heavily borrowed from. I did not find the RI map by accident. After about six months of searching dozens to hundreds of imaginary islands in pirate and Robinsonade fiction I eventually found the RI map (shortly after having found the tin can map).

But I wonder why if the "R.I." map was actually published in 1917 in a popular novel

The map appeared in the 1903 first edition. I already proved this here. Even if you bizarrely refuse to accept this, I will soon own a 1910 reprint with the map and 1910 print date (predating 1917 by seven years). I will post a photograph in this thread by the end of the month.

And is it possible that the Skeleton map was previously known, or that alternate copies of it exist?

No. I can disprove this but unfortunately because of a recent incident, I am hesitant to post certain information here publicly now before I get a peer-review article published. To summarise, the hoaxer c. 1933 copied the Skeleton Island map from the (1903) Rainbow Island map, albeit making minor changes such as removing the most plot-specific place names (to avoid readers realising the map's template was from a novel) but keeping more generic names (or variant spellings of them) and "Smuggler's Cove" notably remains in the same position on both.