THE OVERLAND EOUTE COUNCIL BLUFFS TO OGDEN. 



27 



m 



river, destroying much productive land. The sand-dune areas are 



some 



mounds rising 



100 



more 



above the general surface. The 

 largest bodies of sand extend for 50 miles along the south side of the 

 Platte Valley south and west of Kearney. The mdth of the wider 

 parts of this sand-dune belt is about 3 miles. 



Tlic Overland Route here reaches its southernmost point and turns 

 again toward tlie north. On leaving Kearney the traveler may see 

 the buildings of the State Normal School on the lowland north of the 

 road and an industrial school on the higlilands. 



West of Kearney the bluffs, consisting of loess overlying rocks of 

 late Tertiary age/ are about a mile from the railroad. 



Could the traveler restore the landscape of late Tertiary time^ he 

 would find himself surrounded by scenes greatly different from those 

 of the present. Tlie swampy lowlands were covered with vegetation 

 similar to that now growing in moist climates farther south. He 

 wouhl recognize few of the animals, for there were camels, masto- 

 dons, rhinoceroses, saber-tooth tigers, and other strange beasts, some 

 like those living now only in far-distant lands. (See PI. YT, p. 40.) 

 There were numerous horses, but none of them were like the horses 

 of to-day. In place of the one hoof or modified toe on each foot 

 which the modern horse possesses, his Pliocene ancestor had three.^ 



1 A large part of the central Great Plains 

 is covered, according to N. H. Dart on, by 

 deposits of Miocene and Pliocene age, 

 underlain to the west and northwest by 

 formations of the White River group, of 

 Oligocene age. All these formations lie 

 mainly on the Pierre shale but overiap 

 other formations to a greater or less extent. 

 The average tliiokness is 200 to 300 feet 

 in eastern Colorado and western Kansas 

 but increases to nearly 1,000 feet in parts 

 of western Nebraska and southeastern 

 Wyoming. Probably the entire region 

 was originally covered by later Tertiary 

 deposits that extended far up the flanks 

 of the Rocky Mountains, the Bighorn 

 Mountains, and the Black Hills, as indi- 

 cated by the occurrence of outliers at 



high altitudes. 



a The Pliocene of western North Amer- 

 ica is not well known, but along Snake 

 Creek in Avestem Nebraska there are some 

 deposits referable to this epoch, and from 

 fossils found in them and in rooks of the 

 same age in other parts of the country a 

 considerable number of the animals that 

 lived on the Great Plains during Pliocene 



time are known. Though these animals 

 form an assemblage very different from 

 that of to-day, they much more closely 

 resemble the living animals than those of 

 former ages. Camels and llamas were 

 abundant (see PI. VI, p. 40) and great 

 ground sloths and glyptodontd (see PL II, 

 C, p. 10), whose relatives now live in 

 South America, inhabited western Ne- 

 braska during Pliocene time. Mastodons 

 with tusks on both the upper and the 

 lower jaws, much like those of the Miocene 

 epoch, still persisted. Short-legged rhi- 

 noceroses remained abundant, and there 

 was a great A^ariety of wolf-like carnivora. 

 Saber-toothed tigers and true cats, some 

 of them considerably larger than the mod- 

 ern tigers, were also abundant. Three- 

 toed horses were still numerous, but the 

 modern srenus Eo uus 



not among them . 



time 



le most curious animals 

 Kansas and Nebraska 



gopher-like rodent that had two large 

 horns on its nose. (See PL II, E, p. 10.) 

 Its enormous claws indicate good burrow- 

 ing powers, and its horns also may have 

 been used in digging. 



