BMM0N8.] 



SALT LAKE CITY TO GRAND JUNCTION. 



401 



of which, over and above that used by the railroad, lias has been utilized 

 for irrigation, but as yet without much beneficial effect upon the clayey 



soil. 



Between this station and Agate the northwesterly dipping sand- 

 stones of the Dakota Cretaceous are crossed, and the railroad then 

 descends through variegated clays and sandstones of the Jurassic into 

 the thin-bedded sandstones of the Trias, which it reaches at the Grand 



river. 



The road now runs for over 15 miles (24 km.) along the banks of the 

 river, following its winding canyon gorge, cut in the massive sandstones 

 of the Trias, which form the northern edge of the great Uncompahgre 



plateau. This plateau is an area extending 80 to 100 miles (120 to 161 



SO LIT UDE- 1 



FlO. 'Jl.— Solitude Station. 



km.) northwest from the base of the San Juan mountains, of nearly hori- 

 zontal or gently folded strata of Lower Meso/.oic and Upper Paleozoic 

 age resting uneonf'ormably upon Archean granites and gneisses. The 

 latter rocks arc only exposed in the bottom of some of the many canyon 

 gorges which intersect the plateau. The northern edge of the plateau 

 is formed by an abrupt monoclinal fold, along which the strata bend 

 down so abruptly that they seem to be faulted. The canyon is cut 

 mainly in the massive and nearly horizontal sandstones on the north 

 side of this fold, but at times in its meanderings discloses views of 

 the fold itself. 



Going east, alter reaching the valley of the Grand, the more massive 



beds of the Trias slowly rise from beneath the thinner beds at the top. 



They present on the north of the road magniiicent walls formed by 



vertical cleavage planes and which show tine examples of cross-bedding. 



451 ge 26 



