Prof. Sedgwick on the May Hill SandstonCy 



the " Tabular view '* of the Devonian, Carboniferous, and Per- 

 mian series has been slightly expanded, and a few short expla- 

 natory notes have been added. In other respects, it is, with the 

 mere exception of verbal corrections, word for word as it was 

 submitted to the Geological Society. 



I have the honour to be. Gentlemen, 



Your faithful Servant, 



A. Sedgwick. 

 Cambridge, August 20, 1854. 



This paper is a continuation of one which was read before the 

 Geological Society (Nov. 3rd, 1852), and was afterwards pub- 

 lished in their Journal, vol. ix. p. 215. The results stated by 

 Prof. M'Coy and myself in that paper were as follows : — 



1st. The May Hill sandstone contains a group of fossils es- 

 sentially distinct from those which are found in the sections of 

 Horderley and Caer Caradoc. Its fossils are of a true Wenlock 

 type ; and it must consequently be cut off from the Caradoc 

 sandstone, and arranged as the base of the Wenlock group. 



2ndly. In the great series of beds on the south-western flank 

 of the Malvern Hills, more than 2000 feet of strata, which had 

 been called Caradoc sandstcme, were separated into two distinct 

 groups ; — the lower (Hollybush sandstone and Black shale) 

 being provisionally called Caradoc sandstone and shale; the 

 upper group being the exact equivalent of what we called the 

 May Hill sandstone. Adopting the same nomenclature, we 

 found in the more northern sections, on the west flank of the 

 Malverns, no traces of the Caradoc (or Hollybush) sandstone. 



It was further stated [loc. cit. p. 228), that during a former 

 visit to the Horderley section (made in 1842) I had found beds 

 of shale, with Trinucleus, Caractaci, &c., immediately above Stret- 

 ford Bridge. Now, if this were true, the well known Pentamerus 

 or Hollies limestone must be overlaid by a true Caradoc shale ; 

 and the ascending order of succession must be (as stated in the 

 paper referred to) — " (1) Caradoc sandstone, ending with the 

 Pentamerus or Hollies limestone ; (2) Caradoc shale ; (3) Wen- 

 lock shale ; (4) Wenlock limestone,^^ &c. This conclusion was 

 strenuously opposed by Professor M^Coy ; but we had no oppor- 

 tunity, in 1852, of bringing it to the test. It was derived from 

 an old note-book; and as it made against myself , I thought 

 myself bound to state it. Were the conclusion true, it would 

 only prove, that on the banks of the Onny (as in several sections 

 east of the Berwyn chain) the Wenlock shale is brought by an 

 unconformable overlap, into immediate contact with the true 

 Caradoc group, and without the intervention of the May Hill 



