THE GEOLOGY OF THE ENGLISH CHANNEL. 163 



level of a sea-bed which consists of fine gravel and fine shelly gravel 

 in patclies ; while south and east for some distance from the Eddystone 

 are fine sands. South of the Prawle promontory, off the coast-line 

 from Bolt Head to Prawle, is shell gravel, from Prawle to Start, stony 

 ground. 



The fine sands are quite unlike the silty sand of Plymouth Sound, 

 are coarser as a whole and cleaner. A chart which the writer pre- 

 pared in 1898, from Dr. Allen's details, is here reproduced; the un- 

 determined areas have not yet been fully worked, and perhaps are 

 better left blank until full information is available. There is a little 

 stony ground at East Putts, a stony patch off Stoke Point, and stones 

 have been dredged north of the Eddystone, and on the margin of the 

 Hand Deeps. (Plate XIII.) 



All the stations on this chart are those to which I have elsewhere 

 prefixed the letter A. 



Station A. 100, south of the Eddystone, gave large stones as well as 

 sand. Stations A. 78 and A. 31, although near to and surrounded in 

 part by sand, were actually on rock, and A. 79 yielded Triassic sand- 

 stone. Tliese three points are southward from the Eddystone, on the 

 margin of the fine-sand area. 



The first matter, the probable date of the stony deposits and their 

 origin, may now be left for a time, to be resumed when the general 

 geological mapping of the area has been attempted. 



As to the second matter, the extent to which we may rely on the 

 comparatively local origin of the various stones and pebbles, this, too, 

 may be left in part to a later portion of the paper, but enough should 

 be written here to justify the attempted location of the various forma- 

 tions in situ. 



When a rock is obviously torn from its parent mass, as instanced by 

 its form and freshly-broken surfaces, and when it comes from known 

 rocky, as opposed to stony, ground, the inference as to its in situ origin 

 is almost irresistible. 



This is a matter of rare occurrence. Hunt's H. 19 appears to have 

 been a clear instance. The trawler Pelican got fast in what was sup- 

 posed to be a wreck, and remained thus fast for some hours. When 

 the trawl came away, a fragment of granite showing a clean fracture 

 was found in it. This fragment, No. 19, differs from Hunt's other 

 specimens in that it evidently formed part of a thin slab of rock, and 

 not of a massive block. The stone proved to be a granite of coarse 

 grain, with white and black micas, and a little triclinic felspar in 

 addition to the orthoclase. The locality 20 miles S.W. of Eddy- 

 stone. From practically the same spot, M. 15, the recent dredgings 



