462 Mr. Austen on the 



Flora, so far as it goes, is that of the carhoniferous period. In the black limestones 

 occur Goniatites miscolobus and G. crenistria, mountain limestone species. 

 Strata subjacent to the Carbonaceous Deposits. 

 (Map, PI. XLL, Sect. PI. XLII. figs. 1. to 4, 6. to 8.) 

 The general arrangement and direction of the older rocks of South Devon can 

 be easily ascertained by means of long lines of roofing-slate, chains of lenticular 

 masses of limestone, and subordinate beds of trappean matter ; and by the same 

 means the Devonshire deposits can be connected with those of Cornwall. It was 

 on such considerations as these that I proposed the divisions suggested in 1839*, 

 and which, though purely artificial, may still be conveniently adopted ; they are 

 as follows ; but it is hoped that the map, PI. XLL, and sections, PI. XLIL, will 

 render the proUxity of a mineralogical description unnecessary. 



1. Coral limestone of Newton, Barton, Torquay. 



2. A red deposit, chiefly arenaceous, with a slaty structure, and occasional interchanges of fine fissile 

 beds, extending from Paignton, Windmill Hill, near Berry Pomeroy, and across the Dart about Sharpham. 

 It constitutes also the middle district of South Devon, where it is locally arenaceous, as at Blackdown 

 and Morleigh, and it forms the east side of Plymouth Bay, south of the limestone of Mount Batten. 



3. There is a considerable development of limestone north of the above, and which appears to dip 

 beneath it : such is the position of all the limestone masses about Yalberton, Berry, and the lower lime- 

 stone of the Ogwell country. 



4. Separated from the above by a band of slate, with occasional lines of fine-grained fissile beds fit 

 for roofing-slate, is a lower limestone mass and contemporaneous trappean beds, which ranges from 

 Staple Hill, by Bickington, Ashburton, Buckfastleigh, and Dean Prior. At South Brent these beds are 

 cut off" by the granite of Dartmoor, but they resume their course on the opposite side about Newnham. 

 They cross the river at Saltash, and are continued through South Cornwall, by Tredinick, Polpever, 

 Looe, Fowey, Gorran, St. Michael, and Veryan to south of Falmouth, containing subordinate limestones 

 and calcareous slates, with fossils throughout. 



5. A lowest division may contain all the slate-range north of the foregoing. 



Divisions 1, 3, 4, and 5, have a southern dip. The central portion of South 

 Devon, which includes the red arenaceous series, presents many undulations. Pro- 

 ceeding south the dip of the beds is permanently reversed, and from Kingsbridge 

 to the Prawle it is to the north, so that these strata must be considered as the equi- 

 valents of that part of the section on the north which rises from beneath the Ply- 

 mouth limestone. In both localities are lines of roofing-slate, but limestone bands 

 are wanting in the southern section ; this however is in accordance with a general 

 fact, that the calcareous masses have a southern dip throughout South Devon and 

 Cornwall. 



The rocks of the series above described are well calculated to correct the notions 

 of those who would rely on mineralogical character and structure. The age of 

 the beds between Stoke Fleming and the Prawle, as compared with the rest of the 

 older strata of South Devon, is sufficiently clear ; yet instead of a descending series 



* Geol. Proceedings, vol. iii. p. 123. 



