I found fossil rocks like these in a very limited area in El Paso, TX. I am wondering if they have any value since I have not been able to locate any like these online.
3 1/3" x 2"
Found it while hiking in the desert with my dogs.
Coral and Bryzoa Fossil Stone.
Pennsylvanian Period (323.2 million years ago–298.9 million years ago)
Northern Texas, Southwestern United States.
Dark fossil colony embedded in a limestone matrix. Measurements: 3 1.3 inch x 2 inch, unknown weight.
This book, free to download from Project Gutenburg, looks to be a good introductory resource for the Texas region of the US for fossil identification. https://www.gutenberg.org/files/56315/56315-h/56315-h.htm