312 VIEW OF THE FAUNA OF BRAZIL 



periods, I think it right to add a few remarks respecting the 

 conditions in which the fossils are found. The remains of 

 the larger kinds appear imder the same circumstances as the 

 former family, that is, scattered about in the soil of the ca- 

 verns, and gnawed ; in short, exhibiting unequivocal marks 

 of having been dragged in by beasts of prey. Occasionally, 

 also, I have found the bones of smaller kinds similarly cir- 

 cumstanced, and intermixed with the remains of the larger 

 animals ; so that I am led to conclude that these also have, 

 in some instances, served for food to the Carnivora. But 

 more frequently the remains of these lesser species are seen 

 separate from those of the greater, and forming a kind of 

 osseous conglomerate by themselves. I have in my former 

 paper given a detailed account of the remarkable masses of 

 bones which are collected in these caves, ev^en in our own 

 day, and which I have shown to be attributable to the Strix 

 perlata, Licht. Now, if we suppose an irruption of water 

 penetrating into these caverns, dispersing the heaps of bones, 

 and enveloping the scattered fragments in its sedimentary 

 soil, which, in the process of time, would be impregnated 

 with calcareous particles from the dripping of the roof, and 

 thus be converted into a perfectly hard mass, that would act 

 as a cement to the bones ; under such conditions we should 

 have the very breccia of which I have spoken. Indeed, the 

 resemblance between these osseous conglomerates, and the 

 heaps of bones above described, is so striking, that at the 

 first I was mistaken as to their respective age : ^ for the ani- 

 mals of whose remains they are composed, are in the main 

 the same, being principally species of the genera Mus, Echi- 

 mys, Anoema, or young individuals of Lepus. The total num- 

 ber of the species of this family that at present exist here is 

 eighteen ; whereas I have as yet discovered only sixteen be- 

 longing to the extinct fauna. The genus Mus constitutes a 

 third part of the whole existing number ; and it is precisely 

 this genus that gives the list of recent species its preponder- 

 ance over that of the fossil. But this present superiority of 

 the genus Mus, with regard to the number of species, in all 

 probability arises from our greater ignorance of the ancient 

 fauna. Long before I was acquainted with some of the re- 

 cent species of this genus, now existing here, I possessed 

 hundreds of fragments of their skeletons ; but among these 



' Thus in my description of the cave of Maquine, I have mentioned a 

 similar breccia in its second chamber, which I then considered to be a re- 

 cent formation ; but later investigations have convinced me that the os- 

 seous remains it contains belong to a more ancient fauna. 



