DAVIS : EltKATIC BOULDERS. 
271 
a bay-like hollow in the escarpment of limestone above, at G-, and 
has pressed over the succeeding promontorys, and left a few large, 
and an immense number of smaller masses perched on the limestone 
pavement, or scattered in the clefts of the rock, into which they 
have since fallen. Many lie partially buried in the turf and 
herbage where it occurs. The course of the ice was continued at 
a height of about 1200 feet round the highest part of the hill F, 
but does not appear to have passed over it ; there being no Silurian 
Erratics or other indications of its presence on the top, which is 
100 feet higher. There are several masses perched on the slope 
of the hill side to the westwards ; and a considerable number lay 
scattered over the lower ground southwards in the direction of 
Clapham, the pastures in which the boulders are laid, being about 
700 feet above the sea level. 
The boulders on the Monghton side of the valley are neither 
so numerous nor important as those already described. They 
have been obtained from the Silurian rocks at C and D. It is 
probable that the boulders were formerly much more abundant 
than at present. The land is, for the most part, under cultivation ; 
and the boulders have been broken up and removed. Many, no 
doubt, have been used in building- the fences or walls dividing the 
fields, — they are almost entirely built of Silurian grits and slates, 
with occasionally a large boulder of the same material for a found- 
ation. 
The careful labours of Messrs, Tiddeman, Dakyns, and Good- 
child in mapping the scratches which have been observed on the 
rocks of the Yorkshire dale district and the adjacent country, 
render an explanation of the Phenomena observed at Norber 
tolerably easy. An immense glacier descended from Scotland 
across the Solway Frith, pursuing a southerly course it passed 
along the Eden valley at the foot of the Cross Fell escarpment. 
Still continuing southwards the glacier received considerable 
accessions of ice from the mountains of Westmoreland and Cum- 
berland. A part of the glacier branched off over Stainmoor into 
Yorkshire and Durham, whilst the principal mass persued a course 
