610 
SUBTERRANEAN LAKES. — SNAKE-STONES* 
notice of its running under ground for about two miles, and rising 
again, and spreading' itself into a wide stream. It is also affirmed 
-that there are several of these dipping rivers in Wales, and others in 
the southern counties of England. 
Subterranean Lakes. 
In the canton of Bresse, in Burgundy, there are two subterranean 
lakes, which often overflow in times of the greatest drought, and lay 
a large tract of ground under water. One of them has no apparent 
spring or opening, and yet in a dry season it throws out water enough 
to overflow the meadow-land near it. The grottoes or ca^es of Arcy 
are seated about eighteen miles from Auxerre, and over them is soil 
about ten feet deep. The entrance into these caves is two hundred 
paces long, but narrow. There are arches which form several vaults, 
from whence drops clear water, which turns into a brilliant hard 
stone. Twenty paces from the entrance is a lake which seems to be 
formed by that part of the water that will not petrify. The highest 
of the vaults is not above eight feet. About eighty paces from the 
entrance there is a kind of hall, with a coffee-coloured ceiling, 
wherein there are a thousand odd figures, which have a very agreeable 
effect. 
Snake Stones, or AMMONiLLiE. 
In the old mineralogy, these were a large genus of fossil shells, 
very few if any of which are yet known in their recent state, or living 
either in our own or any other shores ; so that it seems wonderful 
whence so vast a number and variety of them should be brought into 
our subterranean regions. They' seem indeed dispersed in great 
plenty throughout the world, but no where are found in greater numbers, 
beauty, and variety, than in our own inslands. Mr. Harenberg found 
prodigious numbers of them on the banks of a river in Germany. He 
traced this river through its several windings for many miles, and, 
among a great variety of belemnitae, cornua-ammonis, and cochlitse, 
of various kinds, he found also great quantities of wood of recent 
petrifaction, which still preserved plain marks of the axe by which it 
had been cut from the trees then growing on the shore. The water 
of this river he found in dry seasons, when its natural springs were 
not diluted with rains, to be considerably heavier than common water j 
and many experiments shewed him that it contained ferruginous, as 
well as stony particles, in great quantity, whence the petrifactions 
in it appeared the less wonderful, though many of them are of recent 
date. 
Of the cornua-ammonis, or serpent-stones, he there observed more 
than thirty different species. They lie immersed in a bluish fossil 
stone, of a soft texture and fatty appearance, in prodigious nnmbers, 
and of a great variety of sizes, from the larger known sorts down to 
such as could not be seen without very accurate inspection, or the 
assistance of a microscope. Such as lie in the softest of these stones, 
are soft like their matrix, and easily crumble to pieces ; others are 
