150 GEOLOGY OF THE DENVER BASIN. 



streams the Monument Creek formation projects in extended promontories 

 from tin' mesa to the south, often covering the Denver beds for several 

 miles beyond their points of outcrop in the gulches. On the upper part of 

 Cherrj ('reek erosion lias carried the outcrops of the Denver beds in the 

 bluffs of the mesa a distance of nearly 8 miles up the valley, the most 

 southern exposure occurring a little south of Parkers Station, on the Union 

 Pacific, Denver and Gulf Railroad. < >n the west side of the valley, in the 

 broad, low Hat which extends back from the stream for a considerable 

 distance, only the younger formation appears, indicating, in conjunction 

 with the beds cast of the creek, a marked and rapid change in the level of 

 the old lake bottom of Monument Creek times. Over this latter region 

 the Monument Creek probably forms but a thin covering, for in one or two 

 localities, notably in Happy Canyon Gulch, the Denver is found projecting 

 through the overlying formation in the same manner as at the head of 

 Coal Creek. 



The eastward extent of the Arapahoe along the present section is 

 altogether conjectural. The depth of its base beneath the channel of Plum 

 ('reek is probably about SOU feet. 



