82 F. S. Beudant on the Calcareous Tufas of Hungary. 
present day, it would be impossible for the one or the other to 
exist, on account of the form of the mountain. 
With regard to the deposits of tufas, formed by springs which 
still exist at the present day, in the same places, and which con- 
tinually augment the mass in a greater or less degree, there oc- 
cur a very great number in Hungary. All the calcareous moun- 
tains of the counties of Trentsen, Thurotz, Arva, Lipto, Zolyom, 
&c. abound in acidulous springs, which deposit a great quantity 
of carbonate of lime, and of which some have formed, in various 
points, masses so considerable, as in many cases to induce the be- 
lief that their waters were infinitely more abundant than they are 
at the present day. In fact, the present increase of these depo- 
sits is extremely slow ; and were we to calculate, on the same ba- 
sis, the period of time necessary to form such a mass, we should, 
without doubt, find it by much too considerable. It appears 
that there has been a certain period of rapid increase, after which 
the formation has abated to the point at which we see it at the 
present day. It is even to be presumed, that this period is al- 
ready very remote ; for the large hills of tufa have, in the detri- 
tion of their surface, and in the manner in which they are cover- 
ed, either with gravel, or with vegetable soil, &c. a certain air of 
antiquity, something which seems to say that their origin must 
extend to many ages back. It is besides to be remarked, that 
there exist, on many of these hills, churches which appear very 
old, ruined castles, &c. ; and, as I have been assured, there are 
some which are mentioned in extremely old acts and records. 
An inquiry into these details, not only in Hungary, but in many 
other countries of Europe, might be the object of an investiga- 
tion very interesting for the geology of later ages. 
The deposits which are daily forming in the marshes of the 
great plain, and which we have already described, should be still 
regarded as true tufa ; for, although some parts of these depo- 
sits may be owing to a mechanical precipitation of earthy parti- 
cles, there certainly exists also a crystalline sediment for produ- 
cing the solid and compact parts which are used in the plain for 
building. But there is here this difference, that the crystalliza- 
tion takes place tranquilly under the water, while, in the former 
deposits of tufa, it is the result of a continual evaporation in the 
open air, and of the disengagement of carbonic acid, by means 
