ON THE STOCKDALE SHALES. 655 



Secondly, the outcrop along their whole range in the Lake-district 

 proper has been marked in the published maps of the Geological 

 Survey. Thirdly, the equivalent and similar rocks in other 

 areas have been described with a minuteness which is wanting in 

 the case of the other series of the Lower Palaeozoic rocks of this 

 region ; we are therefore likely, by selecting this series, to test the 

 value of these minute subdivisions for purposes of comparison. 



The general features of the district have been so frequently de- 

 scribed, and its structure is so universally known, that it is suffi- 

 cient to remark here that the Stockdale Shales occur on the south 

 side of a great anticlinal, and that they do not appear on the north, 

 as the newer rocks of the northern limb are concealed by the un- 

 conformable overlap of the Upper Palseozoic rocks. Li the southern 

 limb the beds first appear on the eastern side of the Lake-district 

 proper, a few miles to the west of Shap Wells, after which they are 

 traceable with a general E.N'.E.-W.S.W. strike over the valleys of 

 Long Sleddale, Kentmere, and Troutbeck, and across the head of 

 "Windermere to Coniston Waterhead. In this region they dip, 

 usually at a high angle, to the S.S.E., and their course is interrupted 

 by several large north and south faults, the position of which will 

 be seen by reference to the maps of the Geological Survey. (We 

 would here notice that we do not give a map of the outcrop of the 

 beds, as one on a smaller scale than that of the published geological 

 maps would be insufficient for our purpose.) On the western side 

 of Coniston Lake the strike of the beds changes, trending generally 

 in a N'.E.-S.W. direction, and continues thus to Broughton Mills, to 

 the south of which we have seen no trace of the Stockdale Shales, 

 on the western side of the Duddon estuary. On the eastern side of 

 that estuary the beds are brought to the surface by a great anti- 

 clinal fold, and appear in the neighbourhood of Dalton-in-Eurness, 

 where the exposures are poor. In addition to this the Stockdale 

 Shales are also seen in two areas lying on the eastern margin of the 

 Lake-district, — first in the exposure of Lower Palseozoic which 

 is found between the Pennine fault of the Cross-Fell chain and the 

 New Red Sandstones of the Eden valley, where the beds crop out 

 in the neighbourhood of the village of Knock, in the course of 

 Swindale Beck and its tributary, Rundale Beck. Secondly, in 

 the anticlinal which runs along the Rawthey valley, in the neigh- 

 bourhood of Sedbergh, where the shales are seen in the bed of the 

 river at Rawthey Bridge, and in several of the tributary streams, 

 as Hebblethwaite Gill, Cross Haw Beck, and Taith's Gill, on the 

 south side of the Rawthey, and in the stream which runs from 

 Spengill Head, on the north side. Representatives of these beds 

 also occur in the neighbourhood of Ingleton in Austwick Beck, and 

 in Teesdale possible equivalents have been described by Messrs. 

 Gunn and Clough. 



In most places, owing to the small thickness of the series and the 

 high angle of dip, the outcrop is very narrow. This outcrop is 

 nearly at right angles to the direction of the principal streams, so 

 that there are frequent opportunities of seeing the relations of the 



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