522 S. V. WOOD, JUN., OK THE NEWER 



that, besides the presence of lenticular beds of gravel intercalated in 

 it, its character resembles that of the Lower Clay of Lancashire 

 in containing shell-fragments, proving, in my opinion, that it accu- 

 mnlated beneath the sea in such a way as to form its bottom, and 

 not, like the Chalky Clay, by the sliding into the sea of a mudbank 

 which preceded and was immediately followed by the ice. Coming 

 thus south, it passed over low ground forming the trough between 

 the Eastern Moorlands and the Wold, which it blocked up in the east 

 by a thick mass of the Purple Clay, so that the drainage flows from 

 the coast west round the north and west of the Wold into the 

 Humber. This trough, where not thus blocked up, forms the Yale 

 of Pickering, and the Purple Clay does not further enter it; conse- 

 quently it is generally overspread with the gravel that had formed 

 there under water during the later part of Stage II. and during so 

 much of Stage III. as elapsed before it was blocked up. Where the 

 Purple Clay crossed .the eastern end of this trough, and has thus 

 blocked it up, the Filey cliffs show it very distinctly underlain by a 

 Basement Clay which is sharply separated from it, and which seems 

 to be coeval with the Basement Clay of Holderness formed early in 

 Stage 11. ; but whether this extends westwards through the Pickering 

 trough under the gravel, I do not know. Having crossed this part 

 while it was below the sea-level, and so not destroyed the Basement 

 Clay for the reasons I have assigned for the similar escape of the 

 Basement Clay of Holderness, it mounted the Wold scarp subaerially 

 for the narrow space in which this is covered by the clay (and be- 

 yond it to the eastward, where the sea is now), and, descending 

 again, covered the low ground of Holderness that was still submerged, 

 forming the sea-bottom with its moraine. It was the mountain mass 

 of the Eastern Moorlands which, so soon as the decay of the ice of the 

 Chalky Clay gave room for it, or, more strictly perhaps, while this 

 ice still subsisted in the north, parted the stream coming over Stain- 

 moor, and caused that branch to go off to which the clay between 

 the Pennine and the Yorkshire Wold, which ranges through Sheets 

 96, 93, and 87 into the north of 82, was due. 



It seems at first glance paradoxical to suppose, as I do, that the 

 absence of these gravels on the Eastern Pennine slope in Sheets 82 

 and 86 should be due to the Chalky-Clay ice having passed along 

 there, while the presence of drift on the same slope to the north of 

 this should be due to the passing over that portion of the ice of the 

 Purple Clay ; but it must be remembered that, by being fed from 

 the western slope, this latter brought much debris to the eastern ; 

 whereas the former, having its source on the watershed only, could 

 only collect from the first slope it passed down, and carry this to 

 more distant parts ; just as we see, by the great vacant space 

 which is shown in Map No. 1 to exist in the midst of the Chalky- 

 Clay formation in Sheets 51, 66, and adjoining thereto, as well as in 

 the Sheets north and north-west of 70 and 83, it has done even in the 

 lower grounds. As the beds succeeding the Purple Clay in Holder- 

 ness are, as before observed, of flu vio -marine aspect, and at Hessle 

 are underlain by a ripple-marked pan, which is again underlain by 

 a breccia containing mammalian remains, it is clear that these beds 



