Xhiii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



have pointed out that, when he wrote his * Bridgewater Treatise,' 

 Lyell had ah'eady concentrated a flood of hght on the Tertiary strata, 

 but that the transition strata still remained in obscurity, no one 

 having as yet dispelled the darkness which for so long a time had 

 hung over them. Mr. Sharpe was in a different position ; and in the 

 present paper, which describes the geology of the south of West- 

 moreland, the investigation was lighted up by a torch which had 

 already been kindled by Sedgwick and Murchison. Taking as his 

 clue the labours of Sedgwick on the Coniston Limestone, and making 

 that rock the basis of his observations, he established a series of 

 live members, viz. — 



1 . Coniston Limestone. 



2. Blue Flagstone. 



3. Windermere Rocks. 



4. Ludlow Rocks. 



5. Old Red Sandstone. 



Of fifteen species of Silurian fossils in the Coniston limestone, 

 seven belonged to the Lower Silurian rocks of Murchison, and Mr. 

 Sharpe therefore placed it on a parallel with that division, as Mr. 

 Marshall had, on the authority of Sowerby, placed it on a parallel 

 with the Caradoc. The blue flagstone succeeds in conformable order 

 to the Coniston limestone, but contains no fossils ; the faults which 

 have affected one affect also the other, and Mr. Sharpe considered 

 the absence of the fossils to be due to a re-arrangement of the par- 

 ticles in consequence of a metamorphic action. 3. The Windermere 

 rocks, 5000 feet thick, consist of three divisions, — argillaceous schists, 

 schistose grits, and calcareous bands, or calcareous schists. The 

 stratification is much intersected by cleavage planes ; and the few 

 fossils found by Mr. Marshall induced Mr. Sharpe to consider it 

 probable that the lower division might be about level with the sum- 

 mit of the Lower Silurian system, or the base of the Upper. 4. The 

 Ludlow rocks, consisting of hard argillaceous strata, are unconform- 

 able to the Windermere rocks, and contain thirty-four species of the 

 Ludlow Testacea figured by Murchison. 5. The Ludlow rocks almost 

 graduate into the Old Red, which, as in Herefordshire, admits of a 

 triple division. 



In respect to the ages of the disturbances, Mr. Sharpe considered 

 the outburst of the Shap granite subsequent to the deposition of the 

 Coniston limestone and Windermere rocks, but anterior to the depo- 

 sition of the Old Red, the beds of which remain horizontal or un- 

 disturbed ; and that the faults which affected the Old Red Sand- 

 stone, and which also appear to have affected the Ludlow rocks, were 

 of course subsequent to the protrusion of the granite. All the mi- 

 nute and varied effects consequent on such disturbances were de- 

 scribed by Mr. Sharpe, and this paper bears striking testimony to 

 the great ability of its author : that portion of it, indeed, which 

 seems to prove, at least by inference, that the disturbances which 

 affected the lower members of the Westmoreland series were sepa- 

 rated by a considerable interval from those which subsequently 



