348 Abstracts of Memoirs. 
in the neighbourhood of Thirsk, and in the New Red Sandstone 
district near Ripon. 
At Scarborough two well-marked divisions of these deposits were 
shown to obtain; the lower consisting of rolled and often firmly 
compacted gravels, in which were found fragments of the various 
granites of Scotland and Westmoreland, and of the hard blue Car- 
boniferous Limestones of West Yorkshire. Blocks of granite of 
large size were not uncommonly found presenting scratched and 
. grooved surfaces ; but, probably owing to the softer nature of the 
Secondary strata of Yorkshire, no grooving or polishing of these 
rock-surfaces could be found. 
Intercalated with these gravels are irregular beds of sand ; and 
the whole are so arranged as to preclude the possibility of referring 
them to merely aqueous agency; the lines of demarcation being 
sharply defined, and the beds exhibiting distinct angles over which 
other materials are assorted. 
The author described the upper division as composed of uniformly 
compact clay, with occasional seams of pure sand, well exhibited 
towards the northern point of Filey Bay near Scarborough, where 
numerous granite boulders with glacial markings existed in siti. 
The entire thickness of the beds at Scarborough was stated to be 
not less than 200 feet, which was probably their maximum de- 
velopment. 
The author collected the following shells in these glacial beds 
at Scarborough :— 
Mytilus edulis. Tellina Balthica. 
Cyprina Islandica. T. calcarea. 
Venus lincta. Mya truncata, var. Uddevallensis. 
Astarte borealis. 
Mr. J. Gwyn Jeffreys collected in the Boulder-clay at Whitby, 
besides those above numerated, the following :— 
Astarte sulcata, var. elliptica. Balanus porcatus. 
Cardium edule. B. crenatus. 
Pholas crispata. Lepralia. 
Alluding to the absence of univalves, the smaller number of 
bivalves, and their more fragmentary characters, Mr. Leckenby 
pointed out the difference, in these respects, from the Caithness beds 
described by Mr. Peach before the Association in 1862, but which, 
from Mr. Peach’s description, resembled in general features those of 
Yorkshire. 
2. On CHANGES OF THE RELATIVE LEVEL OF LAND AND SEA IN SOUTH-EASTERN 
DEVONSHIRE, IN CONNECTION WITH THE ANTIQUITY OF MAN. 
By W. Prncetty, Esq., F.R.S., F.G.S. 
from a careful examination of the geological evidences that 
can be studied relative to changes of level in Devonshire, Mr. 
Pengelly was led to recognize the following periods of change and 
their several results :—Ist. A remote period prior to the lodgement 
of the gravels now occupying the valley-slopes and summits of the 
