Well, let's deal with the material first. The two main sources of argillite in the Northeast are Lockatong Argillite from NJ/Pa, which from a geological perspective, is actually argillaceous shale. The other source of argillite is southern New England, where I live and hunt. The argillite found here is actually argillaceous slate. More fine grained then Lockatong. Our argillite patinates greenish grey or blue grey. It closely resembles the slate found in the Carolina slate belt, as far as how it patinates.
If I found your piece up here, no question it's one of the varieties of southern New England argillite, or argillaceous slate. That type of argillite is a pretty inferior lithic, and I've photographed some crudely fashioned points to demonstrate its inferior nature. Most of these are also water worn, and it shows:
The last photo above is a Stark point, Middle Archaic. And that brings us to the question of what you found. I can only answer for myself. There may be some damage to your piece, I am not holding it in hand, but, if I found it up here it would be an argillite Stark point. IMHO of course. I am used to that crude lithic, and it really seems obvious enough to me.
Here are some Stark points. That's a New England type name. Stark points can be considered a typological analog to Morrow Mountain points from the Mid Atlantic and further south:
The first piece in the top row of that photo is argillite, as is the 2nd and 4th piece in the bottom row. In your piece I can see the rudimentary flaking characteristic of argillaceous slate, and it looks like a point to my eyes. I guess I'd prefer to hold it in hand to eliminate flake, but especially in the tip area, it seems pretty obvious to me. Other then quartz, it's the most common material I find in Rhode Island....
I've gone over all your photos again. That is the type of argillite I indicated. Argillaceous slate. And it shows the type of flaking I see with such material all the time. I cannot be certain if the stem has any damage, which might alter the actual type, but I can say if I found it up here, there would be no doubt in my mind that I had found a point. I've been picking up points made from that lithic for decades.
