124< PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 21, 



fossil in this upper limestone ; neither did he appear to have ever 

 seen any. In quoting his authority there must, therefore, have been 

 some mistake. Of the singular High Haume limestone I may just 

 remark — that it is mineralogically unlike this upper limestone — that 

 it is associated with a different series of rocks — that it contains a 

 distinct series of fossils (viz. Lower Silurian), and that it is not on 

 the line of strike of the upper limestone. But if we endeavour to 

 identify the two limestones, (as I did myself in 1822, before I had 

 studied the structure of the neighbouring country, or knew the fos- 

 sils,) what then follows ? That through a thickness of not less than 

 4000 or perhaps 5000 feet, there is an utter confusion of Upper and 

 Lower Silurian types. I do not accept this conclusion : and I have 

 now gone over the reasons for the classification I adopted in 184'4, 

 and confirmed by my examination of the same country in 1845. 



I next examined the rocks of Ravenstonedale, Howgill Fells, and 

 Middleton Fells. Their geological base is formed of a calcareous 

 slate with impure beds of limestone, which in two or three places 

 (especially Helmsgill in Dent, and Ravenstonedale, above Rother 

 Bridge,) contain many fossils. I collected in about an hour at one 

 small quarry in Ravenstonedale not less than twenty-five or thirty 

 species*. From the very near agreement of these with Coniston 

 limestone (Lower Silurian) fossils, we have a true geological base- 

 line for the contorted region of Howgill Fells, and we have no lower 

 rocks brought up in that mountainous region. Were these rocks of 

 Ravenstonedale by themselves, and dissociated from the upper 

 groups, there might perhaps be some doubt of their exact age. 

 But they pass upwards into the most characteristic Coniston flags, 

 with Graptolites ludensis and Cardiola interrupta ; and these flags are 

 in their turn surmounted by the hard grits (2) and the Ireleth slate 

 (4). Hence the Howgill Fell system is only a repetition of the four 

 lowest groups on the north-west side of the great fault of the Lune, 

 folded over and over again by vast local undulations ; and hence also 

 it follows that the highest rocks of the Westmoreland series occur in 

 a kind of irregular hollow or basin, with older rocks expanded along 

 their whole eastern extremity: but there is no direct and unequi- 

 vocal proof of any want of conformity in any part of the series till 

 we reach the old red sandstone and the carboniferous limestone. 



* Mr. Salter has given me the following extract from his list of these fossils : — 

 Orthis Actonice. 



——— flabellulum. 



elegantula (formerly 0. canalis), 



alternata, &c. 



like 0. Pecten (repeated at Coniston). 



Leptcena transversalis. 



depressa. 



All the above are known Coniston fossils. The Ravenstonedale list also resembles 

 the Coniston in the rarity or absence of certain fossils which abound at Bala, e. g. 

 Orthis vespertilio, Leptaena tenuistriata, Crania catenulata, and a new species of 

 Orthis. To these may be added some peculiar species of univalves and six or 

 seven species of bivalves which occur neither in the Caradoc of Sir R. Murchison 

 nor in the Coniston limestone. 



