192 RICHARDSON : THE LOWER OOLITIC ROCKS OF YORKSHIRE. 
It will be unnecessary to go into details with regard to the 
geographical distribution of the Cornbrash in Yorkshire or with 
regard to sections of it ; but it may be as well to state that it is 
thinnest ^\here it first appears from beneath the Oxfordian on 
the coast, and thickest away to the west in Newton Dale (see 
Table I.). 
At the time Mr. Paris and I visited the coast between Filey 
and Scarborough, there were some large blocks of dark-coloured 
Cornbrash limestone on the sands of Gristhorpe Bay, which had 
fallen from the precipitous cliffs above. They were full of fossils 
in an excellent state of preservation and are denoted in the 
generalized section on page 213 by an asterisk. The others we 
collected from the ^^•eU-kno^^;^l little reef under the fro^^^ling 
heights of Red Cliff, Cayton Bay, which is said to have yielded 
most of the specimens that are \kow distributed in our many 
museums and labelled as having come from the Yorkshire Corn- 
brash. 
A small outlying j)atch of Cornbrash occurs at the Falsgrave 
Brickworks on the Scarborough and Seamer Road and tumbled 
masses may be examined on the steep slopes of the workings. 
Here the limestone is very '" rotten " and of a deep bro^^n colour ; 
while only casts of the fossils are available. These, however, 
are very " sharp." Amongst the specimens obtained here was 
a piece of an ammonite, which Mr. Buckman calls j\IUcrocephaUtes 
svbtumidus (Waagen). >^ 
II. SUB-DIVISIONS RECOGNIZABLE IN THE LOWER OOLI^^S 
OF YORKSHIRE. 
In Gloucestershire, between the Cornbrash and the Upp'^ 
Lias, is a great mass of rock 2:)redominantly marine. In Yorkshire 
the corresponding deposit is as essentially estuarine : great masses 
of sandstone occur interbedded in the sandy shales, which are 
often rich in plant -remains ; while only narrow bands of relatively 
inconspicuous impure limestone represent the deposits that were 
formed under temporary marine conditions and in many places 
have ill-defined upper and lower limits. But it is to these com- 
paratively insignificant bands that one must turn if reliable data 
for correlation purposes are to be obtained. 
