Natural History of Voleanos and Earthquakes. 59 
has examined, if springs rise in granite, it is just at the bound- 
ary of that formation with a stratified rock. Ina great many 
cases it happens, that part of the springs rise from granite, and 
part from the slate or limestone in contact with it; and, he cor- 
rectly observes, a more striking instance of the immediate con- 
nexion between thermal waters and disturbed strata could not be 
desired.* 
According to the observations of several geologists, the tertiary 
rocks in the Pyrenées extend horizontally to the foot of this 
chain, without entering, as the chalk, into the composition of 
any part of its mass. Elie de Beaumont thence infers that the 
Pyrenées received their position, relatively to the neighboring 
parts of the earth’s surface, between the period of the deposition 
of green sand and that of chalk (a formation, whose raised strata, 
according to Dufrénoy’s observations, ascend to the crest of this 
chain,) and before the deposition of the tertiary strata of various 
ages.t| We can very well explain, according to this supposition, 
why the springs in the Pyrenées issue between the elevated gran- 
ite and the raised strata of slate and limestone. The circum- 
Stance above quoted from Pallasou, viz., that the temperature of 
Springs becomes lower, in proportion to their distance from the 
principal granite-mass, may perhaps be of little importance, since, 
according to the remark of Forbes, cold sulphureous springs are 
to be found, even within not many yards of others, having a high 
temperature, and almost an identical mineral composition. Of 
this he has met with two examples in very different parts of the 
chain, one at the Eaux Bonnes, where a perfectly cold spring 
rises within two hundred yards of the principal hot spring of the 
Place, has similar medicinal properties, and is even more strongly 
iMpregnated with sulphur. The other example occurs at Las 
Escaldas, on the southern declivity of the Eastern Pyrences, 
Where a most efficacious cold sulphureous spring rises within 
about one hundred yards of a hot one. When, Forbes contin- 
ues, to these facts we add others scarcely less curious, of springs 
of totally different mineral composition issuing from nearly the 
IP Suscmmng oe ee Collin telerel 
_" At St Saureur and Thuez, we have the co-ordinate, and, as Forbes p. 602, 
nightly thinks, connected phenomena of intrusive rocks, dislocations or fissures, 
metalliferous impregnation, and hot springs. 
' See Poggendorif’s Annalen, t. xxv, p. 26, also p. 58. 
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