344 



(. H. Hunt — Devonian HocJcs of South Devon. 



The annexed sketch chart of the positions of the crystalline 

 trawled-blocks, prepared long since to compare the relations of th<-se 

 rocks with the granite of Dartmoor, brings out the curious fact that 

 a line drawn from the highest land in Dartmoor into the English 

 Channel, dividing the blocks equally, passes through the centre of 

 the Bolt district. It also passes within about half a mile of StoUi- 

 fortl, North Bolbury, and South Down Farm, whence I have received 

 respectively the most schist-like Devonian diabase, the most horn- 

 blendic of the granular Green Eocks, and the most altered of the 

 qiiartz-schists, in my collection of slides. 



Map showing relative positions of the Dartmoor Granite, the South 

 Devon Schists, and blocks of Crystalline Rocks trawled in the 

 English Channel. 



It only remains for me to render my best thanks to those frieiids 

 who with entire disinteresterlness have assisted me from time to 

 time by instruction and otherwise, in investigating the affinities 

 between the altered and unaltered rocks of South Devon. Without 

 the kindly and varied help of Messrs. Harker and Teall and of the 

 late Mr. Tawney with the rock sections, and that of Messrs. Ussher 

 and Somervail with the rocks themselves, the present paper could 

 scarcely have been written. For all conclusions, and eri-ors, I 

 assume entire responsibility, whilst crediting my aforesaid friends 



