1016 HISTORICAL GEOLOGY. 



to the imperial forests of the Russian Czar in Lithuania. It is said to exist also in the 

 Caucasus. The now extinct Bos primigeniiis is supposed to be the same with the Urus 

 (Ure-Ox, or Bos Urns, described by C?esar in liis Commentaries, and stated to abound 

 in the Gallic forests), and is a distinct species from the Aurochs, with which it has been 

 v:confounded. It is said to have continued in Switzerland into the sixteenth century. 



The American Buffalo (Bos Americanus Gm.) formerly covered the eastern part 

 of the continent, to the Atlantic, and extended south into Florida, Texas, and Mexico ; 

 but now it is practically an extinct species, except so far as it is under human protection. 



The giant Sequoia or Redwood of California is sure to become extinct as a native 

 plant. 



GENERAL OBSERVATIONS ON THE QUATERNARY. 

 BIOLOGICAL PROGRESS. 



Culmination of the type of Brute Mammals. — The biological progress of 

 the Quaternary as it appears in Brute Mammals was but a continuation of 

 the types of the Tertiary onward, to their culmination in the course of the 

 Champlain period. The great average size of the species, in connection with 

 the evidence of unimpaired powers, and also the large number of the species 

 as well as the dense population, are good evidence that Brute Mammals have 

 passed their maximujn development. More than half of the species that, 

 then existed are probably yet unknown. But the facts are sufficient, never- 

 theless, to sustain thfe above statement. The area occupied by the great 

 Mammals extends from Alaska to Patagonia, from Great Britain, and the 

 Siberian shores, to southern Australia. A species best thrives in the region 

 of fittest climate. In the Pleistocene, the fittest climate Avas universal. 

 Geologists have attributed the extinction of most of the species and the 

 dwindling of others to the cold of the Reindeer epoch. It is the only 

 explanation yet found, though seemingly insufficient for the Americas. 



The era of Fishes, as has been stated, was the time of urostlienic Verte- 

 brates, species in which the posterior extremity of the body serves as the 

 locomotive organ ; and the era of Amphibians and Reptiles, the time of 

 merosthenic Vertebrates, the hind legs of the species being the stronger 

 limbs in locomotion. Under, the era of Mammals the merosthenic species- 

 comprise the Herbivores, and many of them are made to serve Man as 

 draught-animals, because of their strong hind limbs ; but the higher Mam- 

 mals, the Carnivores and Quadrumana, are prosthenic, the anterior limbs 

 being not simply locomotive organs, but having some prehensile power, and 

 m the most of the species eminently serviceable in this way. Only carniv- 

 orous and herbivorous species that have taken to a water life are urostlienic, 

 and this they have become by returning to the element that is especially 

 fitted for Fish-like locomotion. 



Relation of the Quaternary to the Tertiary Mammals. — The Quaternary 

 types of fauna and flora on a continent were to a large extent closely related 

 in kind to those of the Tertiary. South America in Pleistocene time was 

 prominently the land of Edentates ; and so, during the Tertiary, Edentates- 



