﻿60 3fK. T. F. SIBLY OS THE FATJXAL SUCCESSION IX THE [Feb. I908, 



the fold respectively brings out features of considerable interest. 

 Detailed measurements of the beds in both limbs of the anticline 

 have been recorded by Mr. H. H. A.ruold-Bemrose, from whose 

 description ^ the thicknesses given in the following account have 

 been taken. 



In the eastern limb of the fold the descending sequence is as 

 follows : — 



Thickness in feet. 



(4) Shales and thin limestones about 17 



(3) Tuff 6 



(2) Shales and thin limestones 26 



(1) Thinly-bedded limestones, compact in texture, with 



chert; shale-partings in the upper portion ... about 100 



That part of the section which comprised (2), (3), & (4) is now over- 

 grown, but the Avhole series of cherty limestones (1) is excellently 

 displayed. As a whole, the cherty-limestone series is poorly 

 fossiliferous ; but certain beds contain fossils commonly, and yield 

 corals and brachiopods characteristic of D3. 



The fold is clearly dissected, and individual beds may be traced 

 from one limb to another. In the western limb the descending 

 sequence is as follows : — 



TJtickness in feet. 



(2) Grey, crinoidal, limestones without chert : to top of 



section 47 



(1) Thinly-bedded, compact limestones with chert 60 



The crinoidal limestones (2) clearly represent the upper portion 

 of the cherty limestones of the eastern limb. They are highly 

 crinoidal throughout most of their thickness, and contain brachiopods 



Pig. 4. — Diagrainmatic section of Xeivton- Grange cutting. 



«=Compact limestone, with chert and shaly partings. /; = Crinoidal limestone, 

 without chert. c= Black shale. 



[Length of section = about 200 yards.] 



in great abundance. In the lower part they have a conspicuous, 

 wedge-like bedding, the beds thickening westwards. At the top of 

 the cutting the gradual change from blue, compact, unfossiliferous 

 limestone with chert into light-grey, highly- crinoidal limestone 

 without chert, may be seen to occur within individual beds as 

 these are followed from east to west. This change of lithological 



1 Quart. Journ. Geol. Soc. toI. lix (1^K)3) p. 339. 



