218 Review of “ Outlines of the 
Upper division of the Oolitic Series. 
The first subdivision of this series is the Purbeck beds. 
From these beds is obtained the Purbeck Marble, and they 
consist of thin strata of argillaceous limestone, alternating 
with schistose marbles. This rock contains subordinate 
beds of workable gypsum and numerous shells ; some of 
which are said to be fresh water shells: also beautiful im- 
pressions oi fish, and the head of a crocodile. 
The Portland Qolite, the next member of the upper 
oolitic system, consists of several beds of coarse, earthy 
limestone. It is quarried extensively and constitutes most 
ale. Extinct genera, allied to the order Lacerta, are 
among the fossils of this clay; and also a species ‘of Ich- 
thyosaurus, a variety of Plesiosaurus? bones, apparently of 
cetacea, and numerous shells. 
Middle Division of Oolites. 
The Coral Rag occurs first in this division. It compris- 
es a series of beds from 100 to 200 feet thick ; the calcare- 
ous matter prevailing in the upper part, and the siliceous 
in the lower. upper beds are a calcareous freestone, 
mmin b- 
quantity. 
The Oxford clay, the second member of this division, 
forms beds of a tenacious and adhesive clay, of a dark blue 
color, of immense thickness: the lower part occasionally 
containing irregular beds of limestone “Iron pyrites and 
selenite occur abundantly in this as indeed in all argillace- 
ous formations.” ‘The organic remains are peculiar and 
