DEVONIAN. 



137 



Champernowne and Mr. Ussher, The Devonian beds in this 

 neighbourhood have been divided as follows by Mr. Ussher: — 



Plymouth. Torquay (See p. 131.) 



Upper Devonian Picklecombe and Staddon Grits Cockington Beds. 



i Green Slates of Rame Head. \ Berry Park and Dartmouth Slates, 

 Lilac and Grey Slates. ) and Ashprington Series. 



Plymouth Limestone Great Devon Limestone. 



Red and Greenish Slates. Lower Slates. 



Lower Devonian. Looe Grits and Schists. Lincombe and Warberry Grits, etc. 



Q 3 



Looe Gn'fs and Schists. — The oldest beds 

 comprise green, red and grey slaty grits, and 

 schistose beds, that are exposed at Looe and 

 Looe Island, west of Plymouth. They con- 

 tain some badly-preserved fossils. The beds 

 of Yealmpton Creek have also been placed 

 on this horizon. 



Red and greenish Slates. — Beneath the 

 Plymouth limestone, grey, red, and greenish 

 slates, with intercalated grits, are exposed in 

 the railway-cuttings between Plymouth and 

 St. German's. North of Plymouth, the 

 lowest beds near Dartmoor consist of grey 

 and drab slates, with lodes and elvans 

 (Buckland and Bickleigh Beds) ; above 

 these come slates with interbedded volcanic 

 materials in great variety (Weston and 

 Compton Beds) ; and higher still, purple 

 and green slates nearest to Plymouth (Mutley 

 Beds).' These names are taken from locali- 

 ties north-east of Plymouth. (See Fig. 19.) 



Plymouth Limestone. — The Plymouth Lime- 

 stone (Plymouth Rag) is very similar in cha- 

 racter to that of Torquay, previously de- 

 scribed. (Seep. 133.) The Plymouth streets 

 are paved with this " marble." The main 

 mass of the Plymouth Limestone terminates 

 in the north part of Mount Edgecumbe 

 Park. It dips southwards under shales, 

 partly calcareous, and associated with ash- 

 beds, and it appears to pass in places into 

 calcareous shales, in the neighbourhood of 

 St. John's, west of Devonport, as noted by 

 Mr. Ussher. 



Lilac and Grey Slates. — Above the Plymouth 

 Limestone come lilac, greenish, and grey 

 slates, with occasional gritty beds. 



1 Pioc. Geol. Assoc, viii. 461. 



- H. B. W., Science Gossip, Aug. 1877, p. 169. 



