264 
FORMATION OF GROTTOES 
In the primitive mountains open to our researches, real 
grottoes, those which have some extent, belong only to cal- 
careous formations, such as the carbonate cr sulphate of lime. 
The solubility of these substances appears to have favoured 
the action of the subterranean waters for ages. The primi- 
tive limestone presents spacious caverns as well as transition 
limestone,* and that which is exclusively called secondary. 
If these caverns be less frequent in the first, it is because 
this stone forms in general only layers subordinate to the 
mica-slate, f and not a particular system of mountains, into 
which the waters may filter, and circulate to great distances. 
The erosions occasioned by this element depend not only on 
its quantity, but also on tiie length of time during which it 
remains, the velocity it acquires by its fall, and the degree of 
solubility of the rock. 1 have observed in general, that the 
w aters act more easily on the carbonates and the sulphates of 
lime ol secondary mountains than on the transition lime- 
stones, which have a considerable mixture of silex and carbon. 
On examining the internal structure of the stalactites which 
line the walls of caverns, we find in them all the characters 
of a chemical precipitate. 
As we approach those periods in which organic life deve- 
lopes itself in a greater number of forms, the phenomenon of 
grottoes becomes more frequent. There exist several under 
the name of baumen,% not in the ancient sandstone to which 
the great coal formation belongs, but in the Alpine limestone, 
and in the J ura limestone, which is often only the superior part 
of the Alpine formation. The Jura limestoneg so abounds with 
* In the primitive limestone are found the Ivuetzel-loch, near Kaufun- 
gen in Silesia, and probably several caverns in the islands of the Archipe- 
lago. In the transition limestone we remark the caverns of Elbingerode, 
of Rubeland, and of Scharzfeld, in the Ilartz; those of the Salzfluhe in 
the Grisous ; and, according to Mr. Greenough, that of Torbay in Devon- 
shire. • J 
f Sometimes to gneiss, as at the Simplon, between Dovredo and 
Crevola. 
+ ^ ie dialect of the German Swiss, Balmen . The Baumen of the 
Sentis, of the Mole, and of the Beatenberg, on the borders of the lake of 
Thun, belong to the Alpine limestone. 
§ 1 may mention only the grottoes of Boudry, Motiers -Travers, and 
'V alorbe, in the Jura; the grotto of Balme near Geneva; the caverns 
between Muggendorf and Gaylenreutk in Franconia ; Sowia Jama. Ogrod- 
fimiec, and Wlodowiee, in Poland. 
