1870.] 425 [Maack. 



in the lower parts of the land. That the ocean extended at an ear- 

 lier period farther inland than it does at the present time, is proved 

 as we shall see, by the fossil remains of the upper tertiary formation 

 of this country. 



The most characteristic feature of this pampa mud is the exis- 

 tence of large and bulky fossils, namely, Megatherium, Mylodon, 

 Glyptodon, Toxodon, etc., the remains of which will always make 

 upon every beholder a deep impression and stimulate him to further 

 investigation regarding the nature of these fossil animals, as well as 

 the sediments which enclose them. We owe, in this respect, a 

 good deal of information to Messrs. Alcide D'Orbigny, Darwin, 

 Owen, Bravard and Burmeister. The latter has devoted himself 

 for the last eight years especially to a careful study of these pam- 

 pean fossils, the results of which are very important. Through 

 liis extraordinary skill in drawing, as well as in the mechanical 

 preparation of these very fragile fossils, Prof. Herman Burmeister 

 has been able to present to the scientific world correct pictures of 

 these large animals, and to found in the Museo Publico of Buenos 

 Ayres, one of the best collections of this kind. We find these fossil 

 remains generally in the lowest parts of this formation, and very 

 rarely at the surface. The best places for finding them are the river- 

 hanks or "barrancas." Wide as is the distribution of these fossils,, 

 not only over the whole Argentine Republic and the Republic of 

 Uruguay, but also further north, to the west as well as to the east, 

 that is to say, to Bolivia, Peru fad Brazil, we find them especially 

 abundant near Buenos Ayres and its neighborhood, including an area 

 of about twenty leagues. The animals, however, which are repre- 

 sented by those fossils, lived in the more elevated parts of the coun- 

 try, and their remains were brought down to the low land by the 

 -currents of the different rivers. The proof of this view is found in 

 the remains themselves, when we take into consideration the maimer 

 In which they are embedded in the pampa mud. We occasionally 

 find a whole skeleton together at the same place; of course, in such a 

 case the animal has died on the spot where it is found ; but more 

 frequently we find the different parts of the body separated from one 

 another, and in such a manner that the more solid and compact parts 

 •of the trunk are together, while the external and more easily separa- 

 ble parts, such as the head, the extremities and the tail, are separated 

 from the rest, and often are embedded in different strata of this sedi- 

 ment. This fact shows that the extinction of these animals could 



