W. A. E. Ussher — Pleistocene Geology of Comical!. 255 



veinstone material ; tin stone as sand and gravel ; 

 microscopic particles of gold. On shelf of bluish, and 

 brownish clay. The roots of marsh plants penetrate 

 the tin ground 4ft. to 5ft. Oin. 



H. N.W. of the Railway Bridge over the high road between 

 Lauivet and the Indian Queens. 



1. Vegetable mould , 6in. to lft. 



2. Angular and subangular stones of quartz, slate, el van, 



schorl rock, slate veinstones, and occasionally granite 3in. to 4ft. 



3. Tin ground like the overburden, but with rounded 



masses of tin ore, often very small ; on shelf of clay 



slate lft. to 2ft. 



I. Gun-deep in St. Denis. 



1. Vegetable mould 6in. to lft. 



2. Gravel, stones of slate, quartz, elvan, schorl rock, and 



occasionally granite 4ft. 



3. Peat lft. 



On 4. Tin ground ; poor. 



J. On N. side of Tregoss Moor. Ancient works resumed at Golden 

 Stream about half a mile S.E. of Castle-an-dinas in St. Columb Major. 



1. Vegetable mould Oft. 6in. 



2. Angular and subangular masses of slate, quartz, elvan, 



schorl rock, veinstones, and occasionally granite; 

 lumps of peat had been previously removed from this 

 bed 5ft. to 6ft. Oin. 



3. Tin ground resembling the overburden, but with more 



numerous fragments of elvan ; the tin ore as gravel 



or sand 2ft. to 3ft. Oin. 



E. Dr. Boase (T.E.G.S. Corn. vol. iv. p. 248) mentioned the 

 occurrence of siliceous sand under diluvial debris in the Stream 

 Works near Hensborough, on the road to Boche. At Tregoss and 

 Boche the tin ground contained quartz and schorl pebbles, and the 

 shelf consists of decomposed slaty felspathic rock. 



L. Henwood (J.B. Inst. Corn. vol. iv. p. 230). Section at Penny 

 Snap (Wheal Prosper, in Alternun) E. of the Drains Biver — 



1. Peat _. 7ft. Oin. 



2. Angular and worn granite, elvan, schorl, and quartz stones 



in pale blue felspathic clay, averaging 5ft. Oin. 



3. Tin ground as above, with tin ore as waterworn sand or 



gravel; on granite shelf 3ft. Oin. 



5 A. The section of the Happy Union Works by Mr. Colenso 

 (1829) has been quoted by several writers, but by none more fully 

 than De la Beche, from whom I extract (Beport, pp. 401, 402, 403), 

 giving the deposits in reverse order. 



1. Rough river sand and gravel, here and there mixed with sea 



sand and silt. A row of wooden piles with their tops 24 

 feet from the surface, apparently intended for a bridge, 

 were found on a level with spring-tide low-water 20ft. Oin. 



2. Sand ; trees all through it, chiefly oaks, lying in all directions 



animal remains, bones of red deer, hog, human skulls (?) 



bones of whales 20ft. Oin. 



3. Silt or clay and layers of stones, a conglomerate of sand, 



silt, bones and wood 2ft. Oin. 



4. Sand with marine shells ; water draining through this bed 



is salt above, fresh below Oft. 4in. 



5. Sludge, or silt, brownish to a lead colour in places, with 



