196 GEOLOGY OF THE DENVEB LASIX. 



Hill stage road crosses the creek in section L9. Just above tins point 

 Denver beds outcrop in the banks of the creek and are shown in numerous 

 fine exposures at intervals along- the stream for 4 miles, or nearly to the 

 dark butte between the forks at the head of the creek. 



The ridge east of Murphy Creek is capped by Monument Creek 

 sandstones or grits, resting, as has been mentioned, upon Laramie at the 

 lower end and for 5 miles up Coal Creek. At this point an unnamed 

 stream enters Coal Creek from the south, in whose banks are good outcrops 

 of Denver beds corresponding to those at the same horizon on Murphy 

 Creek, to the westward 1J miles. The Denver beds also appear on Coal 

 Creek, on both banks, about half a mile above the mouth of the unnamed 

 tributary, and again on the west bank 1 mile farther up. Monument ( "reek 

 beds form the high ridge to the west and come down to the level of the 

 creek next east of Murphy Creek, thus cutting off the Denver beds. These 

 appear again 1J miles farther up this creek in most typical form, a dark 

 conglomerate with many augite-andesite pebbles and very little Archean 

 debris. This outcrop is confined to the bed of the creek at its fork in 

 section 16, and evidently represents a prominence formerly existing on the 

 sea-bottom. Or perhaps it is more correct to say that the Monument 

 Creek beds occurring below this outcrop were deposited in a depression in 

 the sea-bottom, for this insular outcrop of the Denver strata is at about the 

 horizon constituting the lower limits of the Monument Creek in the gulches 

 to the westward, as may be seen by an examination of the map. 



Some of these exposures on this, the eastern limit of the formation, 

 are quite typical, possessing pebbles, leaves, and concretionary masses, and 

 consisting sometimes of quite pure eruptive material. Others are to be 

 identified in the iield only by their visible connection with more typical 

 beds, but so numerous are the outcrops in the chief drains that the 

 relationships are seldom left obscure. 



As to (late Creek but little need be said in this place. Three of its 

 large 1 n-anches head near together west of the head of Murphy Creek and 

 just beyond or above the horizon at which the Monument Creek beds 

 conceal tin; Denver. The line of the two formations can be located very 

 closely in each branch by the red-clay horizon of the upper series, as 



