438 GEOLOGICAL EXCURSION TO THE ROCKY MOUNTAINS. 



Loess-like Pleistocene deposit, which forms a very rich soil, though 

 from lack of moisture the plains appear to be arid, and until irrigated 

 produce little beside the prickly-pear cactus [Opuntia), the soap weed 

 ( Yucca), the sagebrush ( Artemisia), greasewood {Sarcobates), and scanty 

 grasses. This Loess deposit is widely distributed over eastern Colo- 

 rado, and seems to connect directly with that of the Missouri valley. 8 " 



From Denver a number of very interesting excursions can easily 

 be made to points illustrating clearly various features of the foothill 

 geology. At Platte canyon, Morrison, Golden, Ralston creek, Boulder, 

 and St. Vrain's creek, all reached by railroad, one can study beautiful 

 sections of the upturned sedimentary series from the Archean to the 

 Colorado Cretaceous, or, in some cases, to the post Laramie of the 

 Denver formation. The excursions to Morrison, Golden, and Ralston 

 creek are easily made from Denver in one day, returning to the city 

 at night. There are good hotels both at Morrison and Golden. 



EXCURSION TO MORRISON. 

 By Whitman CROSS. 



Morrison is a little village 12 miles (19 km.) southwest of Denver, at 

 the end of a branch of the Denver, Leadville and (lunnison railroad. 

 It is picturesquely situated on the banks of Hear creek, which here 

 issues from the mountains, crosses the monoclinal valley between the 

 Archean and the Dakota hogback, and cuts its way through tin 1 latter 

 to the plains, dust within this gap is the town, with line exposures of 

 the Mesozoic section below the Colorado Cretaceous (dose at hand.* 



Dark red Triassic sandstones at the base of the sedimentary series 

 form the most prominent outcrops seen in the section on the north bank 

 of Bear creek. Above them comes a creamy white sandstone, and 

 above that, forming a low ridge at the base of the Dakota hogback, is 

 a limestone which is burnt for quicklime. This limestone occurs in the 

 midst of red clays and shales. Mr. Eldridge has included these beds 

 in the Triassic part of the section, differing in this from the division 

 adopted by the Hay den survey. 



The smooth western slope of the great Dakota hogback exhibits very 

 beautifully the variegated marls, (days, and shales of the Jura. At a 



# Eig. 2G, on page 139, is a reproduction on half scale of the drawing by W. II. 

 Holmes, published in the llayden report for 1871, p. 3-2. The section given is on the 

 north bank of Bear creek and shows the relationships of the various formations 

 which can be easily visited, from the Archean gneisses of Bear canyon or Mount 

 Morrison on the west, through the sedimentary section beginning with the red beds 

 of the Trias, and extending to the highest known Denver beds in the summit of 

 Green mountain on the east. 



