Since, however, the first pages of this article were written, a discovery has been announced connected with the physiology of the American aborigenes, which, if subsequently verified, will be of much importance, both as to the anthropological classification of the Americans, and as to the natural history of man generally. In a letter addressed to the Academy of Natural Sciences of Philadelphia, and republished in the _Philosophical Magazine_ for July last, is an account of the researches of Dr Lund, who has been for some time engaged in geological investigation in Minas Geraes, a province of Brazil. While examining the caverns of calcareous rocks, he has found in one of them, mixed with the bones of extinct races of animals, human bones, having all the character of fossils; they are stated to be in part petrified, and in part penetrated with iron particles, which gave to them a metallic lustre resembling bronze; they were of extraordinary weight; the crania presented the narrow forehead, prominent zygomatic bones, the facial angle, the maxillary and orbital conformation of the American race. The depression of the forehead in many instances is said to amount to a total disappearance. With the bones was found a smooth stone, about ten inches in circumference, apparently intended to bruise seeds or hard substances. In other caverns were found human bones, but unaccompanied with those of other animals. These facts, if confirmed, will furnish us with most important evidence as to the past state of the Americans, and the ancient history and physiology of the human race; but the novelty of the results, and the recent date of the communication, induce us to abstain from hasty comment.