Mineralogy and Geology. 123 
found in Brazil a great many fossil bones, and among them the head of 
a large tiger related to Felis meganthereon (Ursus cultridens), but it is 
much larger; the upper canine teeth are nearly 10 inches long and 1} 
broad. The French Institute has purchased it for 4000 francs. The 
remainder of the collection, except the duplicates, has been disposed of 
to the British Museum. He promises subsequently to communicate 
some remarks on the occurrence of these fossil bones, and especially 
on that of the human remains, which are found among the bones of 
various extinct animals. He has discovered two kinds of monkeys, 
which approximate to the genera Mycetes and Cebus. A short time 
since also, among a number of pieces of amber (not copal), he found 
some:containing insects, in which distinct: spiders’ webs could be seen 
(thus fossil spiders’ webs !!) ; in some, the webs and also the insects 
hanging in them were evident. 
50. The Oust-Urt, and shores of Lake Aral ; (L’Institut, 605, p. 256.) 
—This region hitherto little known, has been geologically examined by 
M.S. de Hetiwersen. He has ascertained, that at the period when the 
beds of the Oust-Urt were deposited, the Caspian and Aral seas formed 
a single Mediterranean sea; that at the middle of this sea stood a high 
island—the Oust-Urt—at whose foot commence formations of marl and 
sandy clays, in which marine and fresh-water fossils are mingled ; that 
the two seas communicated with one another for a period by a channel, 
and had a common fauna even to the formation of the most recent de- 
posits, which include some existing species. 
51. Infusoria.—EunenBeré has arrived at some remarkable results 
with regard to the prevalence of infusoria in voleanic rocks. They are 
as follows :— 
Numerous and widely extended observations have proved that there 
is an ultimate reciprocal relation between independent infusorial life 
and the volcanic phenomena exhibited upon the banks of the Rhine. 
Voleanic crystals of sodalite, leucite, and probably of augite, consist in 
part of masses of infusoria. 
The voleanic island of Ascension, so destitute of life, animal and ve- 
getable, and even of streams of water, and situated in mid-ocean, pre- 
sents ah enormous mass of volcanic cinders which consist almost wholly 
of organic matters, principally of fibres of plants, along with some fresh- 
water siliceous infusoria. 
Although observation shows that in all parts of the world the infuso- 
ria, prevalent in volcanic rocks, are of fresh-water origin, still Patagonia 
affords marine deposits, constituting masses of i i. 
“The Pyrobiolitic rocks in Patagonia constitute extensive beds 800 feet 
thick, containing no carbonate of lime, and only here and there a little 
sulphate of lime. pt ost b> 
