Newbies First Finds. Not Sure What Any Of These Are.

[grommit]

1

2

3

4

Assuming 1 is scallop

2 is bone or rock?

3 is ammonite

4 is snails / gastropods?

[Mike Murphy]

Welcome to The Fossil Forum, Grommit. The specimens in the first photograph are indeed relatives of the scallop known as Neithea texana. Both the upper and lower valves are present in the photograph. The specimen in the 2nd photograph looks like it might be a section of an ammonite, but it cannot be identified due to the poor clarity of the specimen in the photograph. The specimens in the 3rd photograph are indeed ammonites and represent individual whorls of a turrelitid heteromorph, Mariella (Wintonia) brazoensis . The lower 3 specimens on the right in the 4th photograph are weathered specimens of Ilymatogyra arietina, a pelecypod (clam) and are not snails. The specimen on the lower left may also be Ilymatogyra, but it is too weathered and the view does not allow further I.D. It might be Texigryphaea sp, another pelecypod.

Keep on looking, there is a whole world of fossils out there! These specimens are just the start. You are located in one of the finest areas in the United States for collecting Cretaceous age (65 to 145 million years ago) fossils. There are also some very knowledgeable people on this website that can help you with identifications or point you to the locations of identification sources. As a start, I would recommend that you pick up a copy of Charles Finsley's "A Field Guide to Fossils of Texas", a book that can be purchased at various book stores in the Metroplex. It is probably still available through the gift shop at the Dallas Museum of Natural History as well.

Regards,

Mike

[grommit]

We just found even better ones today. I posted a few in the Questions section under cleaning. Ammonite and snail.

I will get the book you recommended. I am also going to get the NSR field guide.

What fun.

[LanceH]

Looks like someone has been hunting the Mainstreet and/or Grayson formations...

Mainstreet

Grayson

= Kgm on this geo map

We just found even better ones today. I posted a few in the Questions section under cleaning. Ammonite and snail.

I will get the book you recommended. I am also going to get the NSR field guide.

What fun.

[Uncle Siphuncle]

Lance is right. Kgm is shorthand for Grayson and Mainstreet formations undivided. Where mapped separately they will be shown as Kgy for Grayson and Kms for Mainstreet. When mapped undivided these formations are still pretty easy to distinguish based on surface expression. The Kms is generally a resistant, yellow to gray limestone that overlies the softer gray to olive gray Kgy marl and clay. Over time where exposed the Kgy erodes, leaving the Kms as sort of a capstone on the hilltops, forming area topography. Texas has many alternating hard-soft cycles which allow zeroing in in specific formations by reading the surface topography while looking at a geo map.