Another piece of chert? From our area.

[Rock queen]

A really nice preform? Awesome no matter what it is. !

[Butch Wilson]

W :woohoo: W! Nice one!

[CMD]

You're right, nice by any name!

[G10+]

Dang !!! you just keep pulling them out ,,, always looking farward to seeing your post !!! keep them coming

[Hoss]

G10 wrote:

Dang !!! you just keep pulling them out ,,, always looking farward to seeing your post !!! keep them coming

X2

[clovisoid]

Wow, that is a wildly interesting piece.
The material is a little glossy, but it kind of looks like porcelanite to me.  The other thing is the ripples in the flakes look like they crossed over from opposite edge.  Can you post a picture with the light at a different angle to see the flaking better?
Not many groups up there used that flaking and that material to make large bifaces like that.

[11KBP]

clovisoid wrote:

Wow, that is a wildly interesting piece.

  It is interesting Joshua. A large biface of high-grade material with what
appears in the photo as possibly being a large overshot. However it is hard
to be sure from the photo. If the biface does exhibit an overshot then it
could be related to the Clovis culture.

[clovisoid]

Yes, that is exactly what I was thinking.  In some places, eg Texas and Florida, there were later groups that occasionally used overshot flaking to thin and it's really hard to tell paleo from later material.  In Montana, on a biface that size, I can't think of too many other options... The question is what is that flake, and are there any remnants of other overshots on the piece.
Anzick wasn't too far from where this was probably found (if the poster hunts near where her profile indicates.)

[11KBP]

clovisoid wrote:

Yes, that is exactly what I was thinking. 
Anzick wasn't too far from where this was probably found
(if the poster hunts near where her profile indicates.)

As-the-crow-flies ...about 30 miles between Bozeman -and- Anzick.