346 
FOREIGN CORRESPONDENCE. 
By Dk. T. L. PnirsoN, of Paris. 
Bauhree's researches on recently-formed Minerals — Action of Mineral 
Waters upon old Roman Cement — Daihj iwoduction of Zeolites, Fluor- 
Sjmr, Arragonite, ^r. — Plomhierite — Time an important element in 
Geological Experiments — Dele&se on the Metamorphism of Argillaceous 
and Siliceous Roclcs — Earthquakes at the Cape of Good Hope — Appari- 
tion of different hinds of Fish after violent Earthquakes. 
Professor Daubree, of Strasburg, has obliged us with a copy of his 
interesting " Memoir on the Mineral Deposits of the Thermal Springs of 
Plombieres." We hasten to make known to our readers the important 
results contained in this new work. 
The investigations already made concerning the natural beds of those 
minerals, which have been classed in the family of Zeolites,* have led 
mineralogists to believe that water has been active in their formation. 
We have already shown f how M. Daubree has reproduced in his 
laboratory a certain number of Silicates, and how he discovered that 
they had been formed in certain springs at Plombieres since the time of 
the Romans. The present Memoir completes our knowledge of these 
interesting phenomena — and what can be more interesting than the 
formation of a stone before our eyes ! It appears, moreover, that Zeo- 
lites have rarely or ever been artificially produced, and their origin 
has always been more or less enveloped in mystery. 
In order to augment the volume of water in the warm springs of 
Plombieres, the author has been constructing a deep aquaduct, for which 
it was necessary to cut through a crust of cement which the Romans 
formerly spread over the valley where the springs rise. This cement 
is composed of fragments of bricks, variegated sandstone, and lime. It 
has been powerfully acted upon by the mineral waters which come in 
contact with it at a temperature ranging from 50 to 60 degrees 
(centigrade). The lime and the bricks themselves have been thus 
transformed into new combinations, which have crystallised in their 
cavities. Among the products of this transformation, the most frequent 
are certain Zeolites, and especially Chabasite and Apophijllite. The 
former, which is a silicate of alumina and lime, is generally found in 
the spilites of certain basalt formations, in the Tyrol, Bohemia, the 
Hebrides, &c. ; the latter, a silicate of lime and potash, is seen also in 
the cavities of spilite rocks and in the beds of magnetic ironstone in 
Norway, Sweden, &c. The samples taken from the warm springs of 
Plombieres were in perfect, well-defined crystals, and in every respect 
similar to the minerals from the above-named countries. 
Besides these, many other Zeolites are formed at Plombieres, but their 
exact species has not yet been accurately ascertained. M. Daubree 
names, therefore, with uncertainty Scolezite, Uarmotome, and Gismondine. 
He mentions, also, the presence of a probably new species of hydrated 
Ilydratcd Silicates, partly soluble in strong acids. — T. L. P. 
t Vide the Geologist for Feb. , 1858. 
