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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 7, 



§ 3. Structure of the Mountain-chains of Howgill, Ravenstonedale 

 and Middleton, on the east side of the Valley of the Lune. 



I will not here detain my readers with any account of the pictu- 

 resque features of these beautiful mountain-chains, or my rambles 

 through their defiles and precipices. The great undulations of the 

 district are among the most remarkable I have ever studied ; and I 

 would also refer to that break of the strata which ranges up the val- 

 ley of the Lune, and in the upper part of the valley deflects towards 

 the north-west, and is connected with a great trouble which brings 

 up the hard grits (No. 3) at Whinfell Beacon. 



The great difficulty among these extraordinary undulations is to 

 find a true geological base-line on which we may construct a regular 

 and consistent system. Indications of such a base-line I have already 

 pointed out in my former paper ; viz. the appearance of Lower Silu- 

 rian fossils near the range of the great Craven fault through the 

 valley of Dent. A careful examination of the whole fault, and of 

 the slate rocks near it, enables me now to state that there is a good 

 base-line nearly all along the eastern skirts of the troubled district, 

 that base being the Coniston limestone (No. 1 ). The evidence will 

 be best understood by sections. 



12. Section above Ingletox. 



ii. Green roofing slate. 



Ingleton. 



S.E. 



This section unfortunately gives us no fossils*. 



13. Section in theVALLEYorDENT, fromRiSELLand Helmsgill toMioDLETON Fells, &c. 

 N.E. S.W. 



Helms Knot. Dent. Middleton Fell. 



Craven Fault. 



8. Limestone shale. 



/. Mountain limestone showing the passage of the Craven fault. 



4. Slate, &c. of Middleton Fell. 



3. Hard grits — at bottom passing into flagstone, and with many specimens of Curdiola inter' 

 rupta and Graptolites ludensis ; together with three species of Orthoceratites, Spirorbis Lewisii, 

 Alveolites, &c. 



2. Calcareous flagstone with Graptolites ludensis and Cardiolu. 



1. Shale and limestone with fine series of Coniston fossils intersected by porphjTy dykes. 



* The Craven fault must pass somewhere between the two masses of mountain 

 limestone to the extreme left and extreme right of the section, but its exact place 

 is not laid bare. 



