Correspondence — Mr. A. Champernoivne. 575 



DEVONIAN AND OLD RED SANDSTONE. 



Sir, — I wish to call attention to what Mr. Horace Woodward, in 

 his interesting "Geology of England and Wales," says on the above 

 subject. At page 72 of Mr. Woodward's book, and paragraph at the 

 foot of the page, beginning " Mr. Etheridge places these limestones," 

 etc., the reader will notice two principal points : first, the probable 

 conformability of the Culm-measures on the Devonian Limestones, 

 and secondly that the Cockington beds, " similar in character to Old 

 Eed Sandstone," are beneath the Limestones. 



Sir H. de la Beche questioned this last point (see page 72 of the 

 "Report"), . . . "And it becomes difficult to determine whether these 

 Sandstones are higher in the series than the Torquay and Tormoham 

 Limestones, or whether we may consider them represented by the 

 Eed Sandstones occurring amid the beds inferior to the Limestones 

 which extend from Meadfoot Sands to Upham." Dr. Holl went 

 further, and pronounced them higher than the^ Berry Park Slates, 

 and these in their turn higher than the Limestone. 



Assuming, however, that the Cockington beds are the same as the 

 red beds forming the heart of the Torquay peninsula (and the Tor- 

 quay geologists do not appear to be troubled with a doubt on this 

 score), I will venture to add a rider to Mr. Woodward's paragraph, 

 viz., that " Upper South Devon Slates " are a fiction. For the Cock- 

 ington beds, being older than the limestone, will become inverted as 

 they range westwards by Beacon Hill, having the Wildwood and 

 Berry Park Slates conformably between them and the Limestones, 

 and standing in the place of the main mass of Lower Slates. 



In Dr. Holl's hypothetical section of the inversions of the Kings- 

 bridge promontory (page 438 of his Memoir, Q. J. G. S., 1868), as I 

 read it, to whatever dimensions the supposed Upper Slates may 

 swell out, he yet conceives the Eed Grit Group (d) to be higher still. 

 May the Slates be the Lower Slates, and the Eed Grit Group loiver 

 still? 



Before we need work out details and draw boundary-lines, it is 

 manifestly of the utmost importance that we should read our sections 

 aright. The Plymouth Limestone might thus occupy an inclined 

 trough, and we should be relieved from the supposition of such a 

 rapid thinning out as must be the case if it be intercalated between 

 two slate groups. The Sharkham Point Limestone would be 

 similarly circumstanced, its southern outcrop being inverted. 



Speaking, then, in very general terms, grey colours and slaty rocks 

 would mantle round red grit areas, and on the other hand they would 

 surround and support lines or oases of limestone, these being fre- 

 quently doubled on themselves and rarely showing their true summit.^ 

 The Limestone is occasionally brought into abrupt contact with the 

 red beds by faulting, as at Kent's Cavern Coppice on the north side 

 of the Lincombe Hill. 



From my study of the country it appears to me a necessary con- 

 sequence of the Cockington red beds being beneath the Limestones 



^ Perhaps among the highest of the series may be the thin-bedded Eed CljTnenia 

 Limestone of Lower Dunscombe, near Chudleigh. 



