Rev. J. Clifton Ward — Geology of the Lake District. 55 



probably represents an ancient quartz -trachyte. With this slight 

 indication of dying volcanic power over the tract under description, 

 commences another great series of marine depositions quite unaccom- 

 panied by volcanic phenomena. 



C. — Upper Silurian Period. 



Under this heading I will also include the time during which the 

 Coniston Limestone and associated beds were being formed ; phy- 

 sically, in this district, these deposits belong to the Upper Silurian, 

 although, pala3ontologically, they may be the equivalents of Welsh 

 Lower Silurian divisions. 



According to Mr. Aveline's determinations, in the Kendal district 

 the total thickness of these Upper Silurian beds cannot be less than 

 14,000 feet. At the base of this great series lies the only limestone 

 bed — that of Coniston — and throughout are alternations of clayey and 

 sandy deposits, the former much cleaved and folded, and the latter 

 occurring as flags, sandstones, or grits. 



Whether there be a slight unconformity or not between the 

 Coniston Limestone Series and the great overlying group of Coniston 

 Flags, practically the whole forms one continuous succession of 

 sedimentary deposits. 



Although no Upper Silurian beds are found north of their Coniston 

 and Windermere outcrop, there is every reason to believe that the 

 whole series once extended over the now exposed volcanic rocks, for 

 there is nothing in the deposits themselves to indicate a land margin 

 near their present outcrop. 



Physical Conditions indicated. — Such a thickness of beds as that 

 just described implies a continued slow subsidence of the sea-bed 

 during the whole period of deposition. The character of many of 

 the strata decidedly points to shallow-water formation, though it is 

 hard to say from what direction the material was derived. The 

 conditions correspond in great measure to those prevailing during 

 the Skiddaw Slate period ; when, however, the uppermost Silurian 

 beds had been deposited, the Skiddaw Slates must have been buried 

 some 20,000 to 25,000 feet deep, beneath the piled-up volcanic series 

 and the great accumulation of Upper Silurian strata. 



Cc. — Unrepresented Period [Old Bed). 

 Again we come upon a period of time unrepresented by written 

 records, but clearly evidenced by the destruction of the records of 

 the previous periods. This destruction by denudation was carried 

 on to an enormous extent, being accompanied, or rather rendered 

 possible, by great movements of upheaval over the whole tract, which 

 movements were probably most intense along a N.E. and S.W. axis, 

 running through the heart of the present mountain district. If we 

 pile up black cloth in layers to a thickness of ten inches, red cloth 

 upon this to a thickness of twelve inches, and blue cloth upon the red 

 fourteen inches thick, then by bringing some powerful force to bear 

 upon the two ends of the pile, the whole may be thrown into curves 

 and contortions by the lateral pressure, and the centre portions 

 consequently raised above the level of the ends. Imagine, then, a 



