The Portland Stone Wall

Where to look for fossils and what they are.

The diagram (below) on the left shows the cut surfaces of some blocks of Portland Stone and some of their typical fossils. These ones are not fossils of animals or plants, but of the burrows in which the shrimp – like animals used to live.

The right hand diagram shows a small section of the undulating seabed, made of a limy mud. The shrimps burrowed into the mud, eating anything they could find and taking shelter in the burrows. Later, when those shrimps were long dead, the burrows became filled with limy mud of a slightly different which shows up as fossils of the burrows.


An example of the shrimp Callianassa californiensus

 

Fossils in the Portland Stone Wall

Pages 8-9

Page 12