78 Geological Society of London. 
as chalk marl; in another, a dark clay has become yellow or snow- 
white, and these effects are not limited to a small space, but are seen 
extending for four miles through horizontal strata of tuff, which rise - 
occasionally to the height of more than two hundred feet. The 
greater part however of the alterations are referred to what are prop- 
erly called extinct fumeroles, or the action of volcanic emanations 
which have now ceased, but which must at one period have resem- 
bled those of St. Calogero. Some of these have produced veins of 
fibrous gypsum, calcedony, and opal, minerals which must have been 
introduced into the rents in a state of sublimation. 
In some places there are tufaceous marls, regularly alternating in 
thin beds, with still thinner and countless layers of granular gypsum, 
the whole mass being again run through every where by irregular 
branching veins of silky fibrous gypsum. ‘These strata, thus inser- 
sected, present a perfect counterpart to some of the secondary gyp- 
seous marls, both of the keuper and variegated sandstone formations 
in Germany.* 
When reading the Professor’s description of these phenomena, we 
share in the pleasure and surprise which he felt on comparing strata 
of high antiquity with others of so recent a date, and which, more- 
Over, owe a portion of that resemblance to changes now daily in 
progress. 
The writings of Baron Daudebard de Férussac were not devoted 
principally to Geology, but we are indebted to him for several me- 
moirs, and among others for an Essay, published in 1814, on fresh- 
water formations, with a catalogue of the species of land and fresh- 
water shells which were then known to enter into their composition. 
Monsieur de Férussac contributed largely to the Geological section 
of the Bulletin Universel des Sciences Naturelles, a journal, of which 
he was the chief editor and original projector. This Bulletin had, 
for its object, to give a monthly analysis or brief abstract, usually un- 
mixed with criticism, of the contents of all new publications in every 
department of science. ‘The work was first carried on for a year on 
a smaller plan, and then assumed in 1824 its enlarged and perma- 
nent form, being divided into eight sections, one of which was devo- 
ted to Geology, Paleontology, and Natural History. A monthly 
number appeared regularly, on this and each of the other seven sec- 
tions, the whole forming together a large octavo volume. In the or- 
* Liparischen Inseln, p. 41. Leipzig, 1832. 1 
