Vol. 62.1 ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxilf 



I. Events prior to the Uplift which produced the Dome. 



(a) The Formation of the Lower Palaeozoic Rocks. 



The formation of these rocks is important, in so far as their 

 lithological characters affect the present features of the district. The 

 division into three main groups — the Skiddaw Slates, Borrowdale 

 Series, and Upper Slates — has already been mentioned, and we 

 need here note only the dominant characters of the rocks of each of 

 these divisions. The thickness of the rocks of the divisions is still 

 doubtful, and only concerns us indirectly. Clifton Ward estimated 

 the thickness of the Skiddaw Slates at 10,000 to 12,000 feet, that of 

 the Borrowdale Series at about 12,000 feet, and that of the Upper 

 Slates at not less than 14,000 feet ; and, although other estimates 

 differ considerably from these, the figures here quoted will suffice 

 for our purpose. 



The Skiddaw Slates. — The rocks of this group are essen- 

 tially argillaceous. Massive grits of no great thickness are of little 

 importance in connexion with our present subject ; and, although 

 some of the lower beds towards the north-west of the area contain 

 a quantity of arenaceous material through considerable thicknesses 

 of strata, these strata are as a rule finely laminated, differing, so 

 far as their effects upon the surface-features are concerned, in no 

 very marked degree from the more purely-argillaceous deposits. 

 From the physiographic al standpoint, general uniformity of char- 

 acter marks the Skiddaw Slates. 



The Borrowdale Series. — Not only are the rocks of this 

 series, on the whole, harder than those of the Skiddaw Slates, but 

 there is rapid alternation of more and less resistant bands often of 

 considerable thickness, and it is necessary to pay more attention 

 to the variations in the characters of the rocks. Mr. Harker and 

 I have divided them as follows, in descending order : — 



Shap Rhyolites. 



Shap Andesites. 



Scawfell Banded Ashes and Breccias = Kentmere-Coniston Slate-Band. 



Sty -Head Group. 1 



Ullswater Basic Lava-Group = Eycott Group. 



Falcon-Crag and Bleaberry-Fell Andesites. 



1 In my ' ^sotes on the Geology of the English Lake District' (Proc. Geol. 

 Assoc, vol. xvi, 1900), I referred to these rocks under the title ' Garnet-bearing 

 Kocks below the Banded Ashes of Scawfell' as doubtfully intrusive, being 



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