TR.i^NSACTIONS OF THE SECTIONS. 65 



read to tlie Academy at Lausanne, and to a meeting of tlie Society of Natui-al Phi- 

 losophy at that place. 



On the Distribution of Granite Blocls from Wasdah Craig. 

 By Prof. Phillips, M.A., LL.D., F.R.S., F.G.8. 



For more than thirty years the attention of the author has been earnestly fixed 

 on the remarkable facts which have been observed by Prof. Sedgwick and himself 

 in regard to the dispersion of granite blocks, from Wasdale Craig, over higli and 

 low gTound across Yorkshire and certain tracts of neighbouring counties. While 

 in the drainage of the Eden and the large tracts embraced by the northern and 

 eastern branches of the Huniber, and the long depression on the ^^estern side of the 

 carboniferous chain of Yorkshire and Lancashire, these blocks occur even plenti- 

 fully, they are quite unknown in every part of the country to the westward of the 

 parent rock. In tracing the com-se 6i the blocks from the extreme south-east of 

 Yorkshire back to their origin, it is found that they by no means follow the valleys 

 and avoid the heights, but that, on the contrary, with little or no difference, they 

 occur alilce on hills and dales, though not on the very highest, till on Stainmoor, at 

 the north-western extremity of Yorkshire, they appear on surfaces raised 1400 feet 

 above the sea. Through this pass of Stainmoor, which, though so much elevated, 

 is in fact a great transverse depression in the carboniferous chain, the blocks have 

 passed on as through a strait of an ancient sea. At no other point have the blocks 

 crossed the chain. Turning now from Stainmoor to the west, we remark that in all 

 the intermediate country, whether elevated to about 1000 feet above the sea, or only 

 to about 500, blocks of the granite are frequent ; and on approaching the site froni 

 which all have passed, they grow so numerous as even to be counted by hundreds 

 and thousands. The summit of Wasdale Craig, being elevated only 1479 feet above 

 the sea, it is ob-sdously not possible to explain the distribution of rocks which has 

 been sketched, either by the movement of glaciers, or the floatation of icebergs, with- 

 out some particular suppositions in regard to the relative levels of several tracts of 

 land ; even if we leave out of account any perplexity as to the relative levels of land 

 and sea. During a few late years, the author has turned special attention to Wasdale 

 Craig itself, and to the distribution of granite blocks in its immediate vicinity, and 

 he presents a map, showing this distribution for a few miles from the Craig. As 

 already observed, they are too numerous to be counted in all the country for one or 

 two miles to the eastward, whatever be the aspect, or shape, or slope of the ground, 

 while none occur to the westward. Wasdale Craig is itself within the drainage of 

 the Lune. To the north and west of it the summit of drainage between the Lime 

 and the Eden is traced over varying heights, greater and less than that of the Craig. 

 This drainage summit is passed by the blocks, at a level below 1000 feet, on a line 

 a little to the north of east. South-westward of the Craig is the watershed between 

 the Lune and the Kent. This summit appears not to have been passed at all, 

 though in many places it is much below the height of the granite Craig. The 

 blocks are often of very large size : some within two or three miles of the Craig are 

 12, 14, 18 feet, an* even more in the largest dimensions ; and at Thirsk, seventy miles 

 off, a block was found 13 feet in diameter. They seldom appear to have been 

 rolled, but yet, perhaps by ordinary surface waste, they have often become blunted 

 at the angles. The author is convinced, by his frequent examination of the pheno'- 

 mena, 1. that the distribution to such great distances, in directions not confomied 

 to natural courses of di-ainage, can be best explained by the agency of ice ; 2. that 

 it cannot have been eflected by glacier movement on the laud at its present absolute 

 elevation ; 3. that it cannot have been performed by iceberg floatation on an ocean 

 however elevated, if the present relative elevations of the country were tken the 

 same as now ; A. that the excessive abundance of blocks near the Craig, and in the 

 region fronting it to the east, seems to require the supposition of a considerable 

 disturbing force,^ which greatly shattered the Craig, and provided a large quantity 

 of removable blocks before the ice action came on. On the whole, the author sup- 

 poses that during the glacial period such a disturbance took place ; that the lake 

 district was depressed ; that icebergs formed from shore ice, and at moderate depttfs 

 in the sea, canied away many of the loosened blocks, over the region fiir away to 



1864. g 



