3 April 2014
These four slabs, collected at “Fossil Hill,” north of the Cristo Rey laccolith at the Chihuahua (Mexico) / Texas / New Mexico triple point, bear positively-weathering fossils of the benthic foraminiferid called Cribratina, an index fossil for the Albian age / stage:
My field notebook serves as an imperfect sense of scale.
Here’s the Albian in the context of the middle of the Cretaceous period of geologic time, from the International Commission on Stratigraphy’s geologic time scale:
Zooming in closer, you can see they are elongate, with multiple “bubble”-like body chambers:
I plan to image these specimens with our macro GigaPan rig soon, so that you can explore them on your own.