ranging E.S.E. between the Rivers Lune and Wharfc. 3 



on granite. This series ranges by Saddleback, Skiddaw, Grisdale Pike and 

 Dent Hill, and is seen on the margins of Bassenthwate, Derwent, Buttermere, 

 and Crummock waters, forming- smooth insulated mountains down which the 

 streams run in straight hues. Dipping at a moderate angle to the east or 

 south-east, under the argillaceous red rock of Barrow and St. John's Vale, it 

 is overlaid by the second or middle division of slate rocks, which are very dif- 

 ferent in texture and general appearance, and occupy a very dissimilar tract 

 of country. 



Close inspection shows nearly all the rocks of this second series to be gra- 

 nular aggregates, with an argillaceous basis of greenish colour, and consider- 

 able but various hardness. Often mottled with different colours, some appear 

 as if filled with fragments like a breccia ; and others, variegated with nodules 

 of calcareous spar, green earth, and differently coloured quartz or calcedony, 

 have been mistaken for amygdaloid. Greenstone and other '"overlyino-" 

 rocks are rather plentiful in the country occupied by this range of slate, as 

 in the Walk and Castle Crag at Keswick, and on the margins of Wythburn 

 Lake. Quarries abound in the course of this division of slate, which includes 

 the grand mountain ranges of Helvellyn, Langdale Pikes, and Scaw Fell, and 

 the lakes Ulswater, Grasmere, and Ennerdale, 



South of this craggy chain is the line of more recently deposited calcareous 

 slate, or transition limestone, well known to geologists, which ranges across the 

 heads of Windermere and Coniston water to Broughton. It is the lowest rock 

 in the country which has yielded organic remains ; amongst which the following 

 are least rare. — Caryophyllia, Millepora, Spirifer, Producta, Orbicula. 



The rocks which inclose and cover it are of a dark colour, without fras*- 

 ments or nodules, often micaceous, and in a few places productive of organic 

 remains. They are the third and most recent series of slates in this country, 

 and are often seen covered immediately by carboniferous limestone. As this 

 is the series to which the slate rocks belong, the illustration of which is the 

 principal object of the present paper, a more particular account of them will 

 be found useful. 



In hardness these rocks greatly surpass those of the lowest series, and, in 

 consequence, give to the hills which they form a more angular and knotted 

 outline, and a more bare and rugged surface : but in these respects they yield 

 to the middle series, which exhibits the grandest precipices and most alpine 

 forms in the district. Only in Ilougill Fells does their altitude exceed two 

 thousand feet, and it is mostly under one thousand ; so that the whole tract 

 which they occupy is overlooked in one direction from the mountain of the 

 middle range of slate, and in the other from the high summits of the carboni- 

 ferous formation. 



b2 



