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 aperia, six species 

 of Bats, four species of Mus-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. 



No. 15, Vol. II. 3 t 



