Stratigraphy of my neighborhood

[Olenellus]

I am fortunate to live in a fossiliferous neighborhood in Fort Worth Texas.  Not only have I found a strata of gryphea across the street from my house, but I have found pelecypods in my backyard and an ammonite in Arcadia park down the street from where I live.  Just recently I found more gryphea in my yard.  All of the fossils in my neighborhood are, according to my research, Lower Cretaceous in age.  I took one of my grandsons down to one site a mere one hundred yards from my home and he found excellent specimens of gryphea.  (Samples are attached).  Have any of my fellow Texans found gryphea in their locations?    -----  Olenellus

[erose]

Cool beans. Your “Gryphaeas” are now known as Texigryphaea. The pelecypods appear to be of the genus Neithea. There should be quite a few more things in those layers to be found as well. 

you should get a copy of this book:

 

A field guide to fossils of Texas

Book by Charles Finsley

[grandpa]

Gryphaea are found throughout the Mesozoic era and into the Paleogene.  In Texas, they can be found throughout the Cretaceous deposits.  For reference on the use of graphaea sp. as indicator fossils for the lower Cretaceous formations in Texas see:  THE LOWER CRETACEOUS GRYPHAEAS OF THE TEXAS REGION by ROBERT THOMAS HILL & THOMAS WAYLAND VAUGHAN, WASHINGTON, USGS, 1898.  https://digital.library.unt.edu/ark:/67531/metadc1114932/m2/1/high_res_d/report.pdf

 

Based on your reference to Arcadia Park in Ft. Worth being just "down the street" from your house, I'm going to assume that you live near Keller.  The surface exposure in Keller and to the west is Grayson and Main Street.  To the east of Keller starting at around Hwy 1709 @ N. Pearson Ln. is the Woodbine Fm. of the upper Cretaceous.

 

Since you know where you live and where you are hunting much more accurately than I do , you can use this map to determine what exposure you are in:  https://txpub.usgs.gov/txgeology/

 

Hope this helps address your questions.

[Olenellus]

Thanks:

 

I'll check out the references you suggested (Finlay and the digital library).  I didn't know gryphea had a new name.   I appreciate the geological map.  What I would like to find in the park next to my house is another chunk of ammonite, this time a whole one.  

 

---- Olenellus

[erose]

On 11/19/2019 at 3:39 PM, Olenellus said:

Thanks:

 

I'll check out the references you suggested (Finlay and the digital library).  I didn't know gryphea had a new name.   I appreciate the geological map.  What I would like to find in the park next to my house is another chunk of ammonite, this time a whole one.  

 

---- Olenellus

Gryphaea is still a legitimate genus. But most of the species found in Texas and the region have been reassigned into the genus Texigryphaea.  Just like some Exogyras being reassigned to Ceratostreon, Ilymatogyra, Amphidonte, etc.

 

But I couldn't tell you what makes Texigryphaea different from the original Gryphaea other than their overall shape.

[Olenellus]

Hello:

 

In response to the feedback I got back on my texigryphaea found across the street from my house, I extracted numerous samples recently.  Attached to this post is a batch of them I photographed.   Not included in this post are a few that seem different as well as a few pelecypods.  

 

---- Olenellus

[Tidgy's Dad]

Really nice.  

[Olenellus]

Erose:

 

I found a significant portion of an ammonite and a two pelecypods near my site (in the park).  These areas are basically the same formation and age (Early or Lower Cretaceous).  The site I found the gryphea is quite exceptional.  There are so many oysters lumped together it is difficult to discern anything else in the conglomerate.  I've never seen anything like it in my experience collecting fossils in the US.

 

---- Olenellus

[siteseer]

On 11/18/2019 at 3:43 PM, erose said:

Cool beans. Your “Gryphaeas” are now known as Texigryphaea. The pelecypods appear to be of the genus Neithea. There should be quite a few more things in those layers to be found as well. 

you should get a copy of this book:

 

A field guide to fossils of Texas

Book by Charles Finsley

 

 

I don't live near Texas but I have that book too.

 

Jess

[Olenellus]

Siteseer:

 

Thanks for the suggestion.  I've heard of this book.  The next time I'm combing my Texigryphaea site, I'll take a closer look for possible ammonites and/or more pelecypods.

 

---- Olenellus