L354 - Shelly limestone

Middle Jurassic

Location

This rock is made up of well cemented bioclasts. The bioclasts (mainly shell fragments) are poorly sorted, ranging from <1mm up to a few 10s of mm. 
Fine-grained cement fizzes with acid, indicating that it is carbonate. It has weathered to a pale yellow-grey.

Carbonate fossil fragment in a carbonate cement (sparite). The laminated structure of the shells is visible in places. 
Cement contains some hematite (brown regions). 
There are a few epidote grains and some opaque areas.
This is a rudstone (Dunham naming system) or biosparite (Folk naming system).

The shells are not in life position – they have been transported. 
Deposited in moderate to high energy environment. 

shelly limestone