Teacher's Fossil ID

[PaleoNoel]

Hey everyone, today I was speaking with a teacher this afternoon at school and being the well known fossil enthusiast that I am, she brought up that she had found some plant fossils on her in-laws ranch in Colorado. She told me that the ranch was northwest of Denver but could not remember what town or county specifically. When I saw it, I thought it could be from the Cretaceous period Dakota Sandstone as I believe that it extends into Colorado, however I could certainly be wrong and it could be younger or older. I want to know what you all think.

If I need more photos and want me to try to get more details let me know.

[jpc]

Can anyone ID this leaf? The clues don't give us enough.  My minimal leaf knowledge tells me the leaf is Jurassic at oldest, so Cretaceous is a good guess.  The rock could very well be Dakota ss, but there could also be other units with leaves in ss beds. There are a lot of Cretaceous and Paleocene rocks NW of Denver and older rocks as well.

 

I think Dakota is a good guess, but I am curious what others think.

[FossilDAWG]

@piranha might be able to help.  I'm pretty confident this is a Cretaceous leaf.  There are a number of Cretaceous paleobotanical sites in the Denver area.

 

Don

[PaleoNoel]

53 minutes ago, jpc said:

Can anyone ID this leaf? The clues don't give us enough.  My minimal leaf knowledge tells me the leaf is Jurassic at oldest, so Cretaceous is a good guess.  The rock could very well be Dakota ss, but there could also be other units with leaves in ss beds. There are a lot of Cretaceous and Paleocene rocks NW of Denver and older rocks as well.

I think Dakota is a good guess, but I am curious what others think.

 

21 minutes ago, FossilDAWG said:

@piranha might be able to help.  I'm pretty confident this is a Cretaceous leaf.  There are a number of Cretaceous paleobotanical sites in the Denver area.

Don

Thanks for your input guys, I know this a small amount of information to work with. I'll try to get more details tomorrow and hopefully that will help. 

[piranha]

Here are the classic monographs:

 

Knowlton, F.H. 1922

The Laramie flora of the Denver Basin with a review of the Laramie problem.

United States Geological Survey, Professional Paper, 130:1-171  PDF LINK

 

Knowlton, F.H. 1930

The flora of the Denver and associated formations of Colorado.

United States Geological Survey, Professional Paper, 155:1-142  PDF LINK

 

Brown, R.W. 1962

Paleocene flora of the Rocky Mountains and Great Plains.

United States Geological Survey, Professional Paper, 375:1-119  PDF LINK

 

Manchester, S.R. 2014
Revisions to Roland Brown's North American Paleocene flora.
Sborník Národního Muzea v Praze - Řada B, 70(3-4):153-210  PDF LINK