MISCELLANY. 
493 
transition period, in which last is the cavern described; the total length of which, 
from north to south, is 1440 feet, the height being from 30 to 40 feet, and the 
breadth from 50 to 60. It is separated by masses of stalactite into twelve 
divisions, of which only three were known before Dr. Lund explored them. The 
others, especially the innermost, were of such extraordinary beauty, that his 
attendants fell on their knees, and expressed the greatest astonishment. On the 
river Velhas, the banks of which the traveller afterwards traversed, the vegeta¬ 
tion assumes a peculiar character. The inhabitants call the forests catingas 
(white forests). They form a thicket of thorny trees and bushes, interwoven 
with parasitical plants of the same nature. The leaves fall in August, and, from 
the beginning of September till the rainy season, the catingas are as bare as 
European forests in winter. On this excursion Dr. Lund had an opportunity of 
examining nineteen caverns, all of which confirmed his opinion of their geological 
formation. He has collected many remarkable particulars respecting the circum¬ 
stances which must have taken place in a great inundation, as well as respecting 
its effects, and convinced himself, by several indications, that its course in South 
America was from north to south. In three of the nineteen caverns which he 
explored, he found petrifactions of quadrupeds, which he had not discovered in the 
Marquine cavern, viz., Cerous rufus^ Caelogenys^ Paca, Cavia aper'ia^ six species 
of Bats, four species of Miis-lepus Brasiliensis^ and Strix peetata. In the first- 
mentioned cavern he found two species of ruminating animals, far larger than 
those now living in Brazil, and a Megatherium, of the size of an Elephant.— 
Literary Gazette. 
M. Tournet has presented a long memoir to the French Academy of Sciences, 
containing his geological observations in the neighbourhood of Arbresle, in which 
he establishes some well determined affinities between the nature of those rocks 
which have pierced through the upper crust at different periods, as well as their 
directions, the soil which covered them, and their degree of fusibility, as con¬ 
nected with the period of eruption. M. Tournet thinks that the true and only 
primordial sedimentary rock is composed of clay slate, and that this rock, which 
contains the element of mica, being altered or modified in different manners, has 
been transformed into gneiss, mica-slate, &c. He admits four modes of altera¬ 
tion : one is calcination, a second trituration, a third the changes produced by 
penetration and cementation., and the fourth is the influence of the granite which 
transforms it into gneiss, by introducing its feldspath when in a state of fusion. 
3 T 
No. 15, Vol. 11. 
