556 Geological Society : Mr. D. Sharpe on the 



The different formations are described under the heads of,— 

 1 . Coniston Limestone ; 2. Blue Flagstone Rock; 3. Windermere 

 Rocks ; 4. Ludlow Rocks ; and 5. Old Red Sandstone. 



1. Coniston Limestone. — This calcareous band, which has been 

 laid down in great detail by Prof. Sedgwick, was adopted by Mr. 

 Sharpe as the base of his inquiries. It usually rests upon dark 

 brown shale, and consists, in its lowest part, of a hard, dark blue, slaty 

 limestone, from fifty to sixty feet thick at Low Wood ; and in the 

 upper, of thin beds of dark brown shale, alternating with others of 

 blue limestone, which gradually diminish in thickness, and totally 

 disappear towards the top of the formation. The bottom bed of 

 limestone contains very few organic remains, but the shales and 

 thinner calcareous bands abound with casts. A list of fossils given 

 by the author includes fifteen Silurian species, seven of which be- 

 long to the lower Silurian rocks of Mr. Murchison ; and the author 

 places the Coniston limestone and associated shales on the parallel 

 of that division of the Silurian system, but without attempting to 

 define its exact relative position. Mr. Marshall, on the authority of 

 Mr. J. Sowerby, places the Coniston limestone on the parallel of 

 the Caradoc limestone. An exact account of the strike and dip of 

 the rock, the author says, will be found in Prof. Sedgwick's memoir, 

 but the general bearing of the strike of the beds throughout the 

 western part of their course is stated to be north-east, though on 

 approaching Shap more nearly east and west ; and the ordinary dip 

 is stated to be south-east, with an inclination rarely less than 30°, 

 and frequently exceeding 60°. 



2. Blue Flagstone Rock. — The shales of the last deposit pass up- 

 wards into a dark blue flagstone, the strike of which is parallel 

 to that of the Coniston limestone, and the dip is conformable. It 

 is stated to range from the west of Coniston by the village of 

 Torver, the head of Coniston Lake, also south of the Ambleside 

 road to Low Wray, and thence from the east side of Windermere, 

 by Trout Beck and Kentmere, to the neighbourhood of the Shap 

 granite. The faults which affected the Coniston limestone series 

 extend into this deposit. No organic remains were found by the 

 author, but he is of opinion that their absence may be owing to the 

 rearrangement of the constituent particles of the rock when they 

 assumed the slaty structure. 



3. Windermere Rocks. — This vast series of beds, to which Mr. 

 Marshall applied the name of Blawith slate, succeeds conformably 

 to the blue flagstone, and is arranged by the author into three 

 groups, which he calls the lowest, middle, and upper divisions. A 

 line drawn from Coniston Water Head to Lindale, a distance of 

 twelve miles, would cross the beds at right angles to the strike ; and 

 though the same strata are, according to the author, frequently re- 

 peated in a succession of parallel anticlinal ridges, yet he is of opinion 

 that the total thickness of the formation exceeds 5000 feet. 



3a. Lowest Division. — This portion of the Windermere rocks con- 

 sists of gray schistose grits and argillaceous slates, containing thin 

 beds of limestone on the banks of Coniston Lake. The strata are 



