949 ON THE DETRITAL TIN-ORE OF CORNWALL. 
once* or twicet—interrupted by a large formation of peat; but a 
settlement of the one and a growth of the other may have taken 
place at the same time or at short intervals; for—in one case at 
least{—the peat is interlaid by finely-divided granitic matter as 
thin as tissue paper. 
It may not be unworthy of remark that vegetable remains, of 
much the same kinds, occur within short (vertical) distances of 
the tin-ground, both north§ and south|| of the water-shed. 
(V). The deep valleys which formerly opened to the sea, below high- 
water mark, on the south coast of Cornwall, contuin alternations of 
mineral with vegetable matter, and of fresh-water with salt-water 
deposits. Of these several particulars Table III affords a brief 
comparison; from which it appears that at 
CARNON. ** 
A bed of silt without shells 
2 feet thick; 12- feet thick; 
(3). ” » 3d ” 
(1). A bed of silt and shells 
0°8 foot thick; | 
(2). » sand and shells | 
2° feet thick ; 
(4). 60 », sand and shells Ma 
3°5 feet thick ; 
(5). x », silt and shells ! 
(1). A bed of sand and shells .. \ 
are inter. 
laid by 
tm 
[S 
~S 
ot 
> 
ise) 
YY 
Three separate beds of silt 
without shells 12: feet thick; 
are separated by 
-A.. 
12: feet thick. J \ 
1). A bed of silt without shells, 4 
e a 5% feet thick; a= (2). Silt; with great quantities 
(3) 31: "(3 of shells..12* feet thick ; 
° 29 99 99 a : 
* Henwood, Cornwall Geol: Trans: iv, p. 63. Barratt, (De la Beche’s) 
Report, p. 403. 
+ Henwood, Cornwall Geol: Trans; iv, p. 61. 
+ Mr. Ralfs, Ante, p. 213, Notes. 
§ Henwood, Cornwall Geol: Trans: iv, p. 59; Ante, p, 205. 
|| Henwood, Cornwall Geol: Trans: iv, p. 59; Ante, pp. 199, 219. 
q Smith, Geol: Trans: iv, (O.8.) p. 406. Rashleigh, Cornwall Geol. 
Trans: ii, p. 282. Henwood, Jbid, iv, (1828), p.58. Colenso, /bid, (1829), 
pp. 382—37. 
** Henwood, Ibid, iv, p. 58. Taylor, Ante, p. 218. Whitley, Ante, p. 
218. 
