INFERIOR OOLITE SERIES 31 
CHAPTER II 
INFERIOR OOLITE SE1UES. 
9 
(BAJOCIAN.) 
GENERAL ACCOUNT OF THE STRATA. 
AMONG our Jurassic rocks no strata exhibit greater variations 
than do the oolitic limestones and the beds associated with them. 
This is the case with the Great Oolite Series, the Corallian Beds, 
and the Portland Beds ; and perhaps even to a greater extent 
with that portion of the Inferior Oolite Series, which is exposed 
to view. Essentially shallow-water deposits, we find among them 
not only considerable changes in sedimentary character, but 
evidence here and there of overlap, reconstruction, and paucity of 
sediment. 
Broadly speaking, the Inferior Oolite Series includes the beds 
that lie between the Upper Lias Clay and the Great Oolite Series, 
but we find evidences of transition between the overlying and 
underlying strata, in different portions of our area. The Series, 
however, is practically equivalent to the Bajocian formation* of 
d'Orbigny, in the sense in which that term was adopted by 
Oppel. 
As already mentioned, over great part of the area from Dorset- 
shire to the Cotteswold Hills, there is a gradual passage upwards 
from the Lias into the Inferior Oolite, so that there are " passage- 
beds " which, on stratigraphical grounds, may be assigned with as 
much propriety to one division as to the other. The Inferior 
Oolite is overlaid in these regions by the Fuller's Earth, between 
which there is, as a rule, no difficulty in fixing a boundary. 
The earliest classification of the strata was taken from Somerset- 
shire, where in 1799 William Smith recognized the occurrence o 
Freestone overlying Sand, between the Blue Lias and the 1 Fuller's 
Earth. To this Freestone, which was known near Bath as the 
" Bastard Freestone," Smith at first applied the name " Under 
Oolite," from the fact of its underlying the locally more important 
Great or " Upper " Oolite. Afterwards the name Inferior Oolite 
was published by Townsendf in 1813, from information derived 
from Smith, and the name was adopted by Sowerby in 1815. 
The Sand that in the same district occurs at the base of the 
Freestone, was eventually termed " Sand of the Inferior Oolite " by 
* Named from Bayeux, in Calvados (1849). 
f Character of Moses, established for veracity as an Historian. 4to. London. 
1813, p. 105. 
