Naturegirl,
You have a healthy skepticism, and it is warranted regarding the Rockwall information provided in the link. The beauty of the local geology is responsible for the unaltered patterns in the photos that are not contextually cropped. The Upper Cretaceous marls of the Rockwall area are famous for their shrink / swell patterns. This creates the stone and mortar look in the photos. You can see this in these geologic formations from Rockwall to Austin and San Antonio. These same patterns are visible in road cuts that slice through the Austin and Taylor Group formations.
They also are subject to a lot of local faulting that is sometimes filled with calcite as a result of geochemical processes. As the softer clay/shale erodes away, the resistant calcite "dikes" are often left behind. In addition, the "iron rings" are where large pyrite nodules have weathered out of rock on their way to limonite or hematite. Again, these are very common. It's hard to place much credibility in someone's conclusions that overlooked a rather simple geologic identification. Especially, since it is a "headlined" photo for The Quivira Project. These are very common features to anyone that spends a lot of time in these Upper Cretaceous formations.
However, the most amazing oversight is the alleged "effigy" found by Dr. Glenn. This is the photo from the website:
THIS IS A FOSSIL! It is also a testament to the lack of simple research required before making fantastic claims. What Dr. Glenn found is not an effigy, but a premaxilla of an 80 million year old swimming reptile, called a Mosasaur. In short, he found the tip of the snout to (most likely) a
Tylosaurus species of Mosasaur!
I do spend a lot of time in these geologic formations, and 2 summers ago, I found most of the skull of the same type of mosasaur in Central Texas. Below are some photos of my find that show the premaxilla.
Folklore is still with us...now it's digital Something I've learned the hard way is that Fantastic claims require Fantastic Proof. You can research any of my statements above.
