462 On the Agricultural Geology of England and Wales. 



those large boulders, transported at this epoch, over a g-reat part 

 of the north of Europe and America, and over that small portion 

 of the southern hemisphere, in corresponding latitudes, which is 

 now dry land. 



In tracing the erratic tertiaries of England and Wales it is 

 found that a large portion of the detritus of which they are com- 

 posed has been derived from the neighbouring rocks ; and that 

 it has been mixed with much other matter transported several 

 hundreds of miles from the N.N.W. and N.E. 



Dispersion of Cumbrian Erratics. — Of the many districts 

 which furnish rocks of peculiar characters, whose fragments 

 in the erratic tertiaries indicate the direction of the trans- 

 porting currents, there are few more remarkable than the lake 

 district of the north of England — few which furnish rocks 

 of such peculiar mineral characters, and limited to areas so 

 small and well-defined, as to preclude all mistake in the identi- 

 fication of their scattered blocks and smaller detritus, and in 

 tracing the lines along which they have been transported. These 

 peculiar rocks are the granite of Shapfell, the syenitic green- 

 stone of Carrockfeli, and the calcareous conglomerate of Kirby 

 Stephen. Not only have blocks of these rocks, often weighing 

 many tons, been transported northwards, eastwards, and south- 

 wards — chiefly in the latter direction, along the depression be- 

 tween the mountain chains — but they have been borne over great 

 irregularities of surface, eastward across the ridge of Orton and 

 the Vale of Eden — a pre-existing valley containing deposits of 

 the new red unconformable to the disturbed rocks which bound 

 it. This valley crossed, the Penine chain has opposed a higher 

 barrier to their progress eastward, which they have surmounted 

 at one point — the pass of Stainmoor — the lowest pass in that 

 chain opening directly to the west, and 1400 feet above the level 

 of the sea. From this point, as from a new centre, they have 

 radiated down the eastern slope of the chain, traversing the vale 

 of Tees to Redcar, and the vale of York to the Humber. 



The oolitic and chalk ridges of the eastern moorlands and 

 the Wolds have opposed obstacles to their passage, similar to 

 those presented by the Penine chain, though on a smaller scale. 

 These have been surmounted, in like manner, at their lowest 

 points, so that blocks of Shapfell granite lie on the oolite near 

 Scarborough, and on the chalk near Flamborouorh Head. 



The Cumbrian erratic blocks have likewise travelled eastward 

 to the mouth of the Tyne, along the depression caused by the 

 Tynedale-fault, at the northern termination of the Penine chain, 

 though the streams flowing in that direction are quite uncon- 

 nected with the mountains from which the blocks have been de- 

 rived. They have likewise gone northward along the Vale of 



