120 T. M. EEADE ON THE DRIFT-BEDS OF THE 



The Triassic sandstone, Keuper marls, and fibrous gypsum, as a 

 rule, cannot have travelled very far ; but I have one or two sand- 

 stones that may have come from St. Bees. 



I have found one or two pieces of what appears to be hard chalk ; 

 and there are occasional flints found in the drift, and even on the top 

 of Moel Tryfaen. One flint pebble I took from the Boulder-clay in 

 Sefton Park is reduced to a plane at one end ; but whether this is 

 the effect of grinding I cannot tell. It appears most probable that 

 these have come from Antrim. 



If these identifications are correct, it will be seen that all the stones 

 are confined to the basin of the Irish Sea and the river-basins 

 flowing into it, excepting some stray stones that may have come 

 from the Highlands of Scotland. It seems curious that such little 

 patches of granite should have yielded such a harvest of blocks ; but 

 it is noticeable that the largest patch, viz. the Eskdale, has fur- 

 nished the greatest quantity. Probably the reason why the granites, 

 syenites, and other igneous rocks occur in a larger proportion in 

 the Drift than would seem to be due to the area they cover in situ, 

 is that they naturally break out in larger blocks, and, moreover, they 

 are generally found at a high level. 



No Shap-Fell granite has ever been found by me ; nor have I ever 

 heard of its being found on the west side of the Penine chain — another 

 fact proving that the erratic rocks of the area under consideration 

 are confined to the drainage-basin of the Irish Sea. This fact seems 

 to me fatal to the idea of an ice-sheet overriding the great water- 

 sheds, and points to a system of glaciers radiating from mountain - 

 nuclei. The distribution of the erratics, as described, seems unac- 

 countable on any theory excepting that of their being sea-borne. 



CLASSIFICATION AND CONCLUSIONS. 



It now remains to consider the bearings of the facts I have de- 

 tailed, and to attempt to account for the varied and complicated 

 phenomena they present. 



The first part of this paper was published in February 1874 ; so I 

 think it will be readily conceded that whatever errors may attach 

 to my views are not due to the haste with which they have been 

 adopted. 



As my desire throughout has been to form my opinions from the 

 facts as seen by myself, while studying the many very valuable con- 

 tributions that have appeared from other observers, I have purposely 

 adopted a system of natural description rather than of geological 

 labelling, so that I may place my readers as nearly as possible in my 

 own position. 



Pee-deift Surface of the Land. 



I must distinguish the Pre-drift surface of the land from the Pre- 

 e;lacial : the former is the surface form of the rocks if the drift- 

 covering were removed ; the latter is to a great extent a matter of 

 supposition. 



