Many of these fossils have legs and claws preserved in place and can be prepared using an air abrasive tool - dremel doesn't work so well as you tend to chip off the delicate appendages.
Nice detail visible at the anterior rim of the carapace. And a claw appendage at left.
When exposed, the preservation (replacement) on the appendages can be quite remarkable.
More like mottled than dichrous in this example.
Fossil crabs: Notopocorystes dichrous, Upper Cretaceous, Britton fm. for #fossilfriday. Largest is about 3.75 cm.
Collected from below the Lake Lewisville (N TX) spillway several years ago. Crabs and ammonites there are in nodules.
#fossilcollecting #crabs #preservation #geology #paleontology