10 



GUIDEBOOK OF THE WESTERN UNITED STATES. 



blocks of a pink rock known as Sicux quartzite, because tlie rock 

 mass from which they came is exposed near Sioux Falls, S. Dak. 

 Many of the granite bowlders were carried by the glaciers hundreds 

 of miles, for the nearest native rock of this kind occurs far to the 

 north. (For description of glacial deposits see note on pp. 21-23.) 



that the mammoth was well adapted to a 

 cold climate and was covered with a dense 

 coat of wool beneath an outer coating of 

 long, coarse hair, while the contents of the 

 stomach and the partly masticated food 

 found in the mouth showed that the ani- 

 mal fed upon the same vegetation that oc- 

 curs in northern Siberia to-day. * * * 

 This is the smallest of the three Pleisto- 

 cene species— 9 feet [high] at the shoul- 

 der. The mammoth was not peculiar to 

 Siberia and North America, but extended 

 also into Europe, where it was familiar to 

 paleolithic man, as is attested by the 

 spirited and lifelike carAings and cave 

 paintings of that date. Thus, during 



in this Pleistocene fauna. 



Perisso 



this 



hemi 



sphere-" 



Two notable contemporaries of the 



mammoth were the Columbian elephant, 

 ElepTiascolumbi [PL II, B], which attahied 

 a height of about 11 feet, the size of the 

 largest African elephants, and the impe- 

 rial elephant, Ekphas impcrator, the larg- 

 est of the American forms, which attained 

 a height of 13 feet 6 inches. 



*'This great creature [the imperial ele- 

 phant] was characterized not only by its 

 enormous stature but also by the propor- 

 tionately very large size of its grinding 

 teeth and was a sur\-ivor from the preced- 

 ing Pliocene epoch; it is not known to 

 have passed beyond the middle Pleisto- 

 cene and was thus the first of the species 

 to become extinct. In geographical 

 range the imperial elephant was a western 

 form, extending from the Pacific coast 

 almost to the Mississippi River, east of 

 which it has never been found, and from 

 Nebraska southward to the City of Mexico. 

 The meaning of this distribution is prob- 

 ably that this elephant shunned the 

 forests and was especially adapted to a 

 life on the open plains. * * * 



als 



Inh; 



dactyla were represented by horses and 

 tapirs, but not by rhinoceroses; it might 

 seem superfluous to say that there were 

 not rhinoceroses, but, as a matter of fact, 

 that family had a long and varied Ameri- 

 can history and became extinct only 

 during or at the end of the Pliocene epoch. 

 The horses were extremely numerous, 

 both individually and specifically, and 

 ranged, apparently in great herds, all over 

 Mexico and the IJnited States and even 

 into Alaska. All the known species (at 

 least 10 in number) belong to the genus 

 Eqiivs, but the true horse {Equus caballus) 

 to which all the domestic breeds are re- 

 ferred, is not represented. The smallest 

 known member of the genus is the pygmy 

 Equus tail, of ilexico. [These ranged in 

 size from ponies as large as a Shetland to 

 horses that exceeded in size the heaviest 

 modern draft horses.] * * * The Great 

 Plains must have been fairly covered "wdth 

 enormous herds of horses, the countless 

 bones and teeth of wliich, entombed in 

 the Sheridan formation, have given to it 

 the name of 'Equus beds.' * * -^ 



"To one who knows notliing of the geo- 

 logical history of North America it would 

 be natural to suppose that the Pleistocene 

 horses must have been immigrants from 

 the Old World which failed to establish 

 themselves permanently here, since they 

 completely disappeared before the dis- 

 covery of the continent by Europeans. 

 This would, however, be a mistaken infer- 

 ence, for North America was for long ages 

 the chief area of development of the 

 equine family, which may here be traced 

 in almost unbroken continuity from the 

 lower Eocene to the Phocene. On the 

 other hand, it Ls quite possible that some 

 of the species were immigrants." 



Tapirs, which are now confined to 

 southern Asia, Central America, and South 

 America, were abundant east of the ^f issis- 

 I sippi but are not known west of that river. 



