11. — Introduction to the general Structure of the Cmnhrian Mountains; 

 with a Description of the great Dislocatiotis by which they have 

 been separated from the neighbouring Carboniferous Chains. 



By the Rev. ADAM SEDGWICK, V.P.G.S. F.R.S. &c. 



(WOODWARDIAN PROFESSOR IN THE UNIVERSITY OF CAMBRIDGE.) 



[Read January 5, 1831.] 



§ 1. Introduction. 



1 HOPE, in a series of communications, of which this may be considered 

 the introduction, to lay before the Society the results of observations made 

 principally during the summers of 1822, 1823, and 1824, among the Cumbrian 

 mountains, and the neighbouring districts of the North of England. All the 

 central portions of the region, I propose hereafter to describe in detail, is 

 composed of rocks of a date anterior to the old red sandstone, but its outskirts 

 are covered by deposits chiefly of the carboniferous order. On the west side 

 it is washed by the Irish Sea ; and on the east it presses against, and, in part, 

 blends itself with, the great calcareous chain which forms the separation of the 

 waters descending to the coasts of Lancashire and Yorkshire. To the north it 

 is prolonged, through an unbroken zone of mountain limestone, into the plain 

 of the new red sandstone, stretching down the vale of the Eden ; to the south 

 it sinks towards the shores of Morecombe Bay, and terminates in a succession 

 of flat-topped elevations, crowned with precipices of mountain limestone — the 

 remains of a calcareous ridge, once undoubtedly continuous from the higher 

 part of the valley of the Kent to the southern extremity of Cumberland. 



It follows, from this description, and will be still more clearly seen by a 

 glance of the eye over the north-west part of the geological map of England*, 

 that the circular cluster of the mountains here described, presents, through 

 the greater portion of its circumference, a nearly unbroken band of mountain 

 limestone ; and on whatever side it is approached, we are struck with the 

 lameness of the outline of every portion of the calcareous zone, when con- 

 trasted with the fine serrated peaks of the loftier and more central elevations. 



* A new edition of Mr. Greenough's Geological Map of England is now in progress, and will 

 be shortly published. 



