COTTESWOLD DISTRICT. 65 
We observe here that the “ Oolite Marl” has now a definite lithological develop- 
ment. Judging from the collections made by Lycett and Witchell in this district, the 
*Oolite Marl ” has been the principal source of the Gasteropoda, few and scattered 
though they be. ‘The fossils are preserved in a good spathic condition, and often 
beautifully white ; but as the matrix is somewhat unkind, a great amount of scraping 
has in many cases materially injured the ornamentation. Hence these fossils, 
though undoubtedly the best afforded by the Inferior Oolite of the Cotteswolds, 
compare unfavorably with those of Dorsetshire. In consequence of this cireum- 
stance their correlation with the Dorsetshire fossils is by no means so satisfactory 
as could be wished. The Oolite Mar] and part of the Freestones, probably, constitute 
one palxontological horizon, which must be referred to the upper part of the 
Murchisone-zone. For practical purposes, then, we may divide the Murchisone-zone 
of this part of the Cotteswolds into an Upper, or Oolite Marl horizon, and into a 
Lower, or Pea-grit horizon, without attempting to draw a strict divisional line 
between the two. The increasing thickness of the Inferior Oolite will be observed ; 
we started at Burton Bradstock with about 12 feet of limestone, and here we have 
126 feet without including the lowest beds. 
Brrouip, Criexney Hitt, Leckaampron Hitt.—This group must be considered 
together and somewhat briefly. Birdlip is about four miles north-east by north of 
the Nerinewa-quarry at Longridge, and the main quarries on Leckhampton Hill are 
about three miles farther. Orickley Hill lies between, rather nearer to Birdlip. 
The development of the Ragstones continues to differ somewhat from that obtaining 
south ; and hitherto we have failed to find the Guisei-bed in any exposure north of 
the Stroud valley. A deposit, known as the Lower Trigonia-grit, underlying the 
Gryphite-grit, contains a considerable number of casts of Gasteropoda. We must 
turn to the lower division of the Inferior Oolite—to the Freestones, Oolite Marl, and 
Pea-grit. Not that these are by any means rich in Gasteropoda. A most diligent 
search is necessary, and even then the specimens are often very small, little 
better than micromorphs. Mr. P. B. Brodie for many years collected from the Free- 
stones of this neighbourhood, and without his aid I should know very little of 
their contents. Many extremely small Gasteropods have also been obtained by 
breaking open Terebratule, Pholadomye, &c., obtained between Birdlip and 
Crickley. Mr. George, of Northampton, has been kind enough to supply me 
with some of these micromorphs, and my own collector, Mr. Bloomfield, has procured 
several, mostly from the Pea-grit. But there is no notable assemblage of small 
Univalves between the Pea-grit and the Sands. A feware found ina thick-bedded 
stone, which probably corresponds to the horizon in the Lower Limestone at Stroud, 
already mentioned. 
The lines where Nerinwa occurs in the Freestone series of this vicinity are 
somewhat obscure in consequence of the condition of the specimens. But some- 
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