8 



WESTEBN 



composed mainly of a claylike material known as loess. According 

 to tradition these bluffs were used for centuries by the Indians as a 

 common m^eeting ground; here the several tribes held their pow- 



their pipes of peace, or declared hostilities, as their 



smoked 



inclinations moved tliem. The name Council Bluffs was originally 

 apphed to a locahty about 20 miles north of Omaha, where Lewis 

 and Clark held council with the Indians. Later it was transferred to 

 the site of the present city. 



The loess * north of Council Bluffs lies above loose sand nnd amvol 

 known as the Aftoni 



fc» 



is marked by a line of springs, for the underground 

 throuirh them more readilv than it nn^QP^ fhrniicrV» fliA L 



gravt^ 



■I200 



■t/oo 



fpoo 



Figure 1.— Sketch profile of river bluffs near Omaha, Nebr., showing the Aftonian gravels lying between 



two beds of e-lacial till aud covered with thick deposits of loess. 



terial above and below. 



om 



annuals no longer found in North Americ 



mastodons, camels, and many c 



L- (See PL II, p, 10.) 



Tlie name is supposed 



^ Loess is a peculiar silt, claylike loam, 

 or fine-grained sand, wliich strongly re- 

 slsis weatliering. 

 to be derived from the German word 

 losen (to loosen), because of tLe tendency 

 of the material to split off in vertical 

 columns. In color loess is generally buff 

 or yellow'isli browTi, It covers large areas 

 in North America, where its beds were 

 probably formed after the ice of the glacial 

 period had disappeaied 



mode 



origin IS 

 beds of it 



not certainly known. Some 



wind from the valleys where it had been 

 deposited by streams. Others probably 



deposited 



temporarj' 



In places 



it contains bones and teeth of animals and 

 shells of snails. If properly watered it 

 makes good soil. 



^ The animals of the Pleistocene (plice^- 

 toe-seen) epoch (see table on p. 2) are in- 

 teresting because they are nearer to us in 

 time than others of the past and therefore 



most nearly like some animals now living; 

 yet those that lived in North America dur- 

 ing this epoch were very different from 

 those living here to-day. To find the de- 

 scendants or near relatives of the Pleisto- 

 cene animals of North America we must 

 go to other continents, for some of them 

 as far away as India. The North Ameri- 

 animals were doubtless scattered by 

 the changes in chmate that resulted in the 

 advances and retreats of the continental 

 ice sheet during the Great Ice Age. 



The fauna, or assemblage of animals, of 

 early Pleistocene time was varied in char- 

 acter. The animals were adapted to the 

 mild climate that then pre\'ailed and re- 

 mained until after the southward advance 

 of the ice sheet, but were driven away or 

 exterminated before the close of the 

 age, and their place was taken by animals 

 such as are now found only in the frozen 



areas of the North. 

 away and a 

 the present 



melted 



