402 
GRACE : THE GLACIAL GEOLOGY OF FURNESS. 
of them in several papers, but his conclusions are invalidated by his 
failure to distinguish between the insular drift and that from the 
Irish Sea. He seems to have regarded granite as the criterion of 
Upper Boulder Clay ; consequently his Lower Boulder Clay and 
Middle Series are mostly insular drift. The same confusion occurs in 
J. D. Kendall's* paper in 1880. 
B. Smith, f in his paper or the Glaciation of the Black Combe 
District, deals with some of the phenomena produced by the ice at 
the head of the Duddon estuary, and his observations seem to fit 
consistently with those recorded below. In the latter part of his paper 
he suggests that the water accumulating in the Duddon estuary 
must have escaped somewhere to the south along the coastline of 
Furness." This has turned out to be an accurate forecast of what 
we have found. 
The Pre-Glacial Condition of Furness. 
It is generally admitted that at the beginning of the Glacial 
Period the Lake District had been above sea level for a considerable 
period, and that the agents of normal denudation had been at work 
for a sufl&cient time to reduce it to what Prof. Davis has termed an 
area of Subdued Relief." The present condition of High Furness 
is very far from this type of topography, and must be regarded as, 
largely, the product of the abnormal erosion of the Glacial Period. 
The Ordovician area abounds in angular rocky scenery — the well- 
known vertical crags and canal-like valleys — which are the antithesis 
of Prof. Da^^s's flowing curves, while the Silurian area contains several 
large basin-like depressions not hitherto described, which it is 
difficult to regard as the result of normal erosion. 
These are : The Coniston Basin, The Lowick Basin, The Broughton 
Beck Basin, The Duddon Estuary and its continuation northwards to 
Woodland. Of these the Coniston Basin is the most important, and 
we propose, therefore, to discuss its origin in detail. (See map of 
High Furness, Plate XLIX.). 
It is composed of two separate valleys, which have originated 
quite independently. These valleys are a considerable distance apart 
at their southern ends, but merge into one another in the north. The 
more westerly is the straight valley running from Woodland to Torver 
♦ Quart. Journ. Geol. Soc, Vol. XXXVII. (1880), p. 29. 
t Quart. Journ. Geol. Soc, Vol. LXVIII. (1912), p. 402-448. 
