367 
ings, thus carrying off the waters by four outlets. All these four 
cataracts of Velinus, Mercatus describes* as much narrower than 
when first opened, and alarming the Reatines, lest the increasing 
stone should cause the lake to extend its bounds, and destroy their 
charming country . 
Nor is their overflow the only inconvenience which waters, pos- 
sessing this property, occasion to those who live in their neighbour- 
hood ; since the continual deposition, and increase of stony matter, 
in every crevice, and in all loose soil, in which they penetrate, and 
on every spot on which they rest, is also a source of disappoint- 
ment ; those parts being thus rendered stony and barren, which had 
perhaps been allotted to corn and pasturage. Thus the passage of 
the water having been interrupted in the subterranean passages of 
the Claudian aqueduct of Rome, the water, soaking into the bibu- 
lous earth, and penetrating into the surrounding cavities, formed an 
extensive quarry of this tufaceous stonef. At Matlock, is a re- 
markable stratum of this kind, which, according to the account 
given by Dr. Dobson, in l774j, was 500 yards in length, in several 
places j nearly 100 yards in width ; and, in the thickest parts, from 
three to four yards in depth. The manner in which this great body 
of stone had been produced. Dr. Dobson remarks, is easily ascer- 
tained Within the memory, he says, of some persons now alive, 
the waters of Matlock were not appropriated to the purposes either 
of bathing, or of drinking. They issued from near the bottom of 
the hill, which lies to the west, immediately behind the present 
houses, and ran, at random, down a declivity of about 100 yards, 
to the river Derwent. In their course they formed large petrified 
masses, intermingled with great quantities of petrified moss, nuts. 
* Metallotheca Vaticana, p. 252. 
-f Roma Vetus ac Recens, &c. Auctore Alexandro Donato, p. 400, 1725, 
Philosophical Transactions, vol. Ixiv. 
