Dr. WJieelton Hind — The Yoredale Series. 161 



whicli is the bed of limestone next above the Great Scar Lime- 

 stone in Wenslejdale, when traced south, gradually, by a thinning 

 out of the intervening beds, approaches and becomes one with the 

 massif below, so that the bottom bed of one subdivision of rocks 

 becomes one with that next below it ; and, on the other hand, in the 

 Ingleboro area, other thin limestones, with intercalated beds of shale 

 and sandstone thinning out south, named the Gayle and Hawes 

 Limestones, appear between the Hardraw and Great Scar Limestones, 

 so that it cannot be said that the line chosen was that at which the 

 massif of limestone ceased to split up. Traced northward, the 

 Great Scar Limestone becomes separated into distinct beds, by 

 wedges of sandstones and shales, so that, although in Wensleydale 

 only from eight to ten separate beds of limestone are recognized, at 

 Alston Moor there are twelve limestones, and in Northumbei"land 

 Westgarth-Foster recognized nineteen. Indeed, it may be laid down 

 as a marked fact that, as the Carboniferous beds are traced from 

 south to north, the organic deposits become thinner, intermittent, 

 and separated by sedimentary beds which thicken in the same 

 direction, and thus, by degrees, the series of Carboniferous rocks so 

 typical of Derbyshire passes gradually into that series which 

 obtains in Northumberland and Scotland. Calcareous deposits are 

 essentially different in origin from those of sandstone, clays, and 

 similar materials ; for they are almost entirely derived from the 

 remains of living organisms, and not from terrestrial denudation. 

 Sandstones and clays, on the other hand, owe their origin to the 

 waste material and detritus removed from land-surfaces by the 

 action of water, chiefly in the form of rivers, and consequently 

 denote a deposit in comparativelj' shallow water, laid down at no 

 great distance from shore. 



In Derbyshire and North Staff'ordshire the Carboniferous Lime- 

 stone is practically all in one mass, containing, howevei', several 

 beds of Toad stone ; ^ although there may occur thin shaly partings 

 of a few inches in thickness, a good example of which is to V)e 

 seen in the quarry opposite the High Tor at Matlock, and in 

 Corabsdale, where, in the upper part of the limestone near Matlock 

 Bath, a thin coal, with its underclay, was found. 



Above the main mass of limestone there may occur, locally, a few 

 feet of thin limestones, alternating with shales and limestones, as 

 at Bntterton Moor, North Staffordshire ; but no marked beds of 

 limestones occur in the 2000-3000 feet of shales and sandstones 

 which overlie the limestone. 



Towards the top of the limestone, and occupying the base of the 

 escarpment at Castleton, whence it can be traced for many miles 

 along the same horizon, is a well-marked sea-beach, with rolled 

 shells and fragments, and an occasional quartz pebble. This was 

 discovered by Messrs. Barnes and Holroyd, who have described the 

 beds in a recent paper read before the Manchester Geological Society. 

 This beach deposit came on gradually, reached a maximum, and 



' See Arnold-Bemrose, Quart. Journ. Geol. Soc, vol. l, 1894, pp. 603-644. 



DECADE IT. TOL. IV. NO. IV. 11 



