IOWA ACADEMY OF SCIENCES. 59 



against its steeply inclined strata. As a range it is unlike 

 any other in America, being in fact a great lofty plateau 

 of nearly horizontal strata, which at the north and south 

 edges are sharply broken and thrown into highly inclined 

 portions. * * * The upper plateau region is deeply 

 carved by the erosion of the glacial period into a network 

 of immense amphitheaters opening downward into a series 

 of ice-worn canons. * * * It is a type of mountain 

 architecture only paralleled by the uplands of the Cau- 

 casus." Perpetual snow occurs on the north side of more 

 than thirty peaks, with a rich alpine vegetation in the 

 meadows below the snowy banks. The high table lands 

 above the timber line become dry soon after the disappear- 

 ance of the snow. From the xerophytic table-lands one can 

 see the foothills and mountains covered with a belt of conif- 

 erous woods, with opening xerophytic parks, numerous 

 lakes and meadows just below the timber line. Altogether 

 it is a region rich in its floristic aspects. 



The xerophytic vegetation of the Uintah mountains 

 varies with the different physiographic conditions and geo- 

 logical formations. From Green river basin to the sum- 

 mits of Gilbert, La Motte and Wilson Peaks, one naturally 

 expects a very varied flora, because of the different alti- 

 tudes. Up to 9,500 feet the Green river basin and 

 Black's Fork, have some plants in common. The succession 

 of plant societies in this region is well marked, and gives 

 us on the whole the history of the succession of plant life 

 since the quarternary. 



The foothill and mountain floras change successively 

 from the hydrophytic to mesophytic, then to xerophytic, 

 and finally in the foothills culminates in the mesophytic, 

 interspersed with a few hydrophytic areas. The varying 

 conditions cause structural adaptations of the plants to 

 their environment. 



1 shall attempt to give very briefly some of the main 

 features of this interesting flora. 



