270 



ME. E. WITCHELL ON THE BASEMEJJT-BEDS 



show a well-marked dividing line between the pisolitic beds and 

 those beneath. 



If the lithological character of the Lower Limestone differs so 

 greatly from that of the Pea Grit, its palaeontology presents a still 

 more striking difference. There are few fossils to be found in the 

 beds of white oolitic limestone, as the meagre list given below will 

 show ; but there is a fossiliferous zone in the lowest bed of the sandy 

 limestone or zone of Ammonites opalinus, although the character of 

 the rock is such that it is impossible to extract the fossils except at 

 great cost of time and labour. The upper beds of white oolite have 

 yielded a few minute Gasteropods, some of them almost microscopic ; 

 but these are the only results of very diligent search. On the other 

 hand, a very large number of Gasteropoda, Brachiopoda, Echinoder- 

 mata, and Conchifera came in with the Pea Grit, many of which are 

 of large size and peculiar to the deposit ; for instance, the genus 

 Nerincea is represented by six species, three of which have not been 

 hitherto described. The advent of so many species of this genus 

 (Nerincea), and of another species in the Yorkshire oolite of con- 

 temporary age, is remarkable, if this was the first appearance of the 

 genus, as stated by Woodward, and furnishes an additional reason 

 for separating the Pea Grit from the Lower Limestone beneath it. 



The following fossils have been collected from the White Oolitic 

 Limestone. 



Ceritella acuta, Mor. Sf Lye. 

 Cerithium geniculatum, Ter, S^'Jour. 



, n. sp. 



, sp. 



quadricinctam, Goldf. 



, var. 



, sp. 



Monodonta Lyellii, Archiac (young). 

 Nerita hemisphsei'iea, Homer (young). 

 Rissoina, n. sp. 

 Kilvertia, n. sp. 

 Turbo, sp. 

 Brachytrema, n. sp. 



Discussion. 



Mr. Etheeidge remarked upon the difficulty of following the 

 paper without a knowledge of the district. Mr. Witchell had de- 

 termined the position of certain new beds, which Dr. Wright and 

 others had overlooked. He further commented on some confusion 

 arising from the use of the terms Pea Grit and Pisolite. Most 

 of the escarpment-sections are obscured by talus. He commented 

 on the thickness of the Pea Grit at Birdlip, and expressed his belief 

 of the value and correctness of Mr. Witchell's views for the Stroud 

 area. He also spoke of the microscopic characters of the fossils of 

 the beds described. 



Mr. HuDLESTON observed that the object of this paper was to de- 

 scribe an important series whose position had been misunderstood. 

 Its distinctive character had not been recognized, and it had been 

 confounded with the Pea Grit, from which it differed both litholo- 

 gically and palseontologically. Both Dr. Wright and Dr. Lycett, it 

 seems, had misunderstood the position of this Lower-Limestone series 

 in the Stroud area. He could thoroughly endorse Mr. Witchell's 



