COTTESWOLD DISTRICT. 05 



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 circum- 

 stance their correlation with the Dorsetshire fossils is by no means so satisfactory 

 as could be wished. The Oolite Marl and part of the Freestones, probably, constitute 

 one palgeontological horizon, which must be referred to the upper part of the 

 Murchisonce-zone. For practical purposes, then, we may divide the Murchis once -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. 



Birdlip, Crickley Hill, Leckhampton Hill. — This group must be considered 

 together and somewhat briefly. Birdlip is about four miles north-east by north of 

 the Nerincea-qu&rry at Longridge, and the main quarries on Leckhampton Hill are 

 about three miles farther. Crickley 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 Terebratulce, Pholadomyce, &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 few are found in a thick-bedded 

 stone, which probably corresponds to the horizon in the Lower Limestone at Stroud, 

 already mentioned. 



The lines where Nerincea 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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