1868.] HOLL SOUTH DEVON AND EAST CORNWALL. 443 



lower slates to the north-west. This view, no doubt, would have 

 the merit of simplifying the structure of the country south of 

 the Culm -measures, inasmuch as it would bring the limestones of 

 South Pctherwin, Padstow, the Looe river, and St. Germans into 

 relation with those of Plymouth and Torbay on one horizon ; and, 

 as will be shown hereafter, although the distribution of organic life 

 in these rocks is very irregular and often local, nevertheless palac- 

 ontological records would not altogether discountenance it. But 

 however plausible this interpretation may appear at first sight, all 

 the direct evidence obtainable, as already stated, is entirely against 

 it ; and whether we cross the country from Bickington by Hobbin 

 Wood to Chircombe Bridge, or from Ashburton by Woodland to 

 Torbryan, or, further to the south, from the granite by South Brent 

 to Black Hall, near North Hewish, we appear to have a clear up- 

 ward succession of the beds ; and in the two or three instances in 

 w^hich the volcanic rocks were observed to have exerted any influence 

 on the contiguous slates, it was on the Ashburton side only *. 



There is equal difficulty in regarding the Plymouth limestone as 

 the same as those of Milladon and the Looe river, brought up to 

 the surface by an anticlinal axis with the intervening beds troughed 

 in between them, notwithstanding the apparently horizontal thinning- 

 out of the limestone at each extremity, and the contortion seen at 

 St. John's. This view would, of course, require the beds contained 

 in the synclinal trough west of the Looe river, as they trended up 

 to the Lyhner and the Hamoaze, to become inverted, and in this 

 position to range eastward to the granite north of Ivy Bridge, 

 where, partly by the granite and partly by faults, the continuity of 

 the belt of rocks became destroyed. But we cannot assume this 

 view without doing violence to the apparent relations of the bedding 

 on either side of the mouth of the Seaton river ; and there is, in 

 fact, no direct evidence to bear it out. Moreover it would bring 

 these beds into relationship with the rocks which certainly overlie 

 the limestones of Plymouth and Brixham on the south, and occupy 

 the whole of the Dartmouth and Kingsbridge district, with which, 

 notwithstanding a considerable resemblance in lithological character, 

 there is no palaeontological evidence to connect them ; whereas the 

 rocks which are seen beneath the limestones at Mudstone Bay and 

 Meadfoot Sands are related to them by similarity of fossil contents, 

 and more especially by their fish-remains. On the other hand, the 

 slates which occupy the country between the Ogwell and Ashburton 

 limestones resemble, both petrologically and in the abundant asso- 

 ciation of volcanic rocks, the beds which, brought down from the 

 Liskeard district by St. Germans and Saltash, and from the coast by 

 Polbathick and by Anthony, are continued by Plympton to the 

 southern extremity of the granite at Ivy Bridge. 



But a directly opposite interpretation has also been suggested 

 respecting the stratigraphical relations of these beds, viz. that the 



* In this I am borne out by Mr. Godwin-Austen, who regards the limestones 

 of Ashburton and St. Germans as a lower range. (Trans. Geol. Soc. vol. vi. 

 p. 462 ; also Sedgwick and Murchison, I. c. p. 653.) 



