﻿Vol. 66.] JURASSIC STRATA OF SOUTH DORSET. 79 



This Sandford Lane bed was only worked once, for economic 

 purposes, about 1875. It was opened up again specially for the 

 purpose of the paper on the ' Bajocian of the Sherborne District '. x 

 It is evident that the collecting that can have been done from this 

 deposit must be a mere scratch of the surface ; yet the results are 

 remarkable, and the beautiful preservation of the Ammonites is 

 extraordinary. 



At a few other localities evidence of a deposit of Shirbuimia date 

 can be detected by a few ill-preserved Ammonites : for instance, at 

 Dundry (Somerset), and in the Grvphite Grit of the Cotteswolds ; but, 

 for all practical purposes, the quarry of Sandford Lane is the one 

 place in the kingdom, known at present, where the deposit could be 

 studied, and that place has been closed these 40 years. 



Ancolioceras. — The finding of Opalinoid Ammonites in the base of 

 the murchisonce bed has before now led to the supposition that there 

 was a certain mixture of forms of murchisonce and opalinum (scissum) 

 zones. The explanation would appear to be that what has been 

 regarded as the base of murchisonce is really of an earlier date. 



At Chideock Quarry Hill the lower part of the Wild Bed is of 

 different matrix from the upper part : it yields a Lytoceratoid, but 

 does not furnish any Ammonites of the murchisonce pattern. In 

 the neighbourhood of Beaminster, strata at the base of 'murchisonce 

 yield Ancolioceras cariniferum and similar forms ; but they were 

 not associated with Ammonites of the murchisonce types. Around 

 Crewkerne (Somerset) there are several species more or less allied 

 to Ancolioceras costatum, and they seem to be somewhat peculiar to 

 that district (* Monogr. Inf. Ool. Amm.' Suppl. 1899, p. xlix). 



At Misterton, which is near Crewkerne, the strata hitherto 

 regarded as early murchisonce yield Lytoceratoids of the style of 

 Pachylycoceras aalenianum. At Chideock the bed yielding the 

 Lytoceratoid is in position above the scissum bed and below the 

 murchisonce bed; and is distinct from both by its matrix. Pre- 

 sumably then the Misterton strata are on the same horizon. 



At Chideock in the murchisonce part of the Wild Bed is a 

 characteristic brachiopod, Zeilleria [ Walclheimia] anglica. This is a 

 noticeable species, which may be followed a long way. 



At Chideock the strata dated Ancolioceras are below the anglica 

 horizon. At Haselbury Mr. Hudleston recorded a thickness of 

 2 feet 5 inches between the anglica horizon and the ' Base Bed ' 2 

 (presumably scissum). 



In my descriptions of strata of the Sherborne District 3 the 

 anglica horizon is marked as 0; and a lower level (P), 2 and 3 feet 

 thick, was noted for Halfway House and Louse Hill. But the P 

 noted for Marston Koad (op. cit, p. 490) is apparently wholly or in 

 part scissum.] 



1 Quart. Journ. Geol. Soc. vol. xlix (1893) p. 479. 



2 'Monogr. Brit. Jurass. Gasteropoda' (Pakeont. Soc.) 1887, p. 41. 



3 Quart. Journ. Geol. Soc. vol. xlix (1893) p. 489. 



