260 On the SuQcession of Rocks in the District of the Lakes. 



from the paler blue slate of the last division) are manufactured in 

 the district between Ulvcrston and Broughton ; which is well si- 

 tuated for sliipping, either I)y the river Duddon, or l)y the canal 

 at Ulverston. Most of these roclxs exhibit a slaty structure, and 

 it has been stated that some of them had two distinct cleavages, 

 meeting and crossing each other under a certain angle ; but a 

 person accustomed to the nianufacture of roofing slates would 

 smile on being told that he might cleave them in any other than 

 one direction. Although little difference has hitherto been made 

 bv writers, between the roofing slate of these three divisions, yet 

 a workman of moderate experience will readily distinguish them. 

 A preference is given to the slate from some quarries, as requiring 

 less weight for the covering of a roof of given dimensions ; this 

 does not depend so much on the specific gravity of the different 

 slates, (which varies from about 2/60 to 2800,) as upon the fine- 

 ness of grain, which enables it to bear splitting thinner. All 

 these rocks effervesce more or less with acids; they contain some 

 calcareous spar, and pvrites, but little metallic ore of any kind; 

 lead ore has been found near Stavely, but in very small quantity. 

 In those districts where the rocks are of a slaty structure, the 

 roads are generally smooth, the fragments naturally adapting 

 themselves to a flat surface, not rolling about like rounded stones, 

 nor presenting angles like rough broken ones : but in low situa- 

 tions, or, where roads are n;uch iised, they are too soon con- 

 verted into a clavey matter. 



A stratum of dark blue rock, which bassets out near Cartmel, 

 on Benson Knot, and Tenter Fell near Kendal, and other places, 

 breaks equally in all directions, and appears to be the parent rock^ 

 from which have been produced a great portion of the rounded 

 stones found in the beds of the rivers Kent and Lune, with those 

 turned up by the plough in the district between these two rivers, 

 and in the parish of Cartmel ; and furnishes materials for paving 

 the streets and repairing the roads in those places. 



Rounded stones of various sizes, from the smallest gravel to 

 the weight of several pounds, held together by a ferruginous cal- 

 careous cement, form a conglomerate rock, extending from Mell- 

 fell, to the foot of Ullswater. 



A bed of limestone forms an irregular circle round this moun- 

 tainous or slaty district, intervening between that and what are 

 called the coal measures. It bassets out near Egrcmont, Lam- 

 plugh, Pardshaw, Papcabtle, Bothel, Ireby, Caldbeck, Berrier, 

 Dacre, Lowther, and, after a circuitous course through West- 

 morland, appears near Ken<lal, Witherslack, Cartmel, Dalton, 

 and Milium, whence for some distance its plnce is occupied by the 

 sea. The most considerable mineral production of this limestone 

 )8 iron ore, which is raised in great quantities in Low Furuess ; 



as 



