EXTENT OF THE DENVEE. 187 



These strnta are underlain by clays like those of the upper portion of 

 the Arapahoe series, and it seems quite probable that the actual line of 

 separation between the two formations is here shown. The rising ground 

 to the southward carries the junction line to the westward, and outcrops 

 of decided Denver strata are found due west of the Reform School in the 

 bed of Kinner Run just below the ditch and old railroad grade crossings. 

 In all intervening portions of Kinner Run the stream bed is excavated in 

 alluvial deposits. At the point just mentioned, however, friable, leaf- 

 bearing sandstones are shown with a dip of 27° to 30 c in an easterly 

 direction, and a strike about X. •_'<> W. Microscopical examination reveals 

 beyond a doubt the characteristic composition of Denver beds. Less than 

 500 yards to the eastward the cut made for the ditch in the north edge 

 of the terrace upon which the Reform School stands exposes horizontal 

 beds of fine-grained conglomerate or grits of the same formation, while less 

 than 300 yards to the westward the Arapahoe conglomerate is found with 

 an easterly dip of 70° or more. 



The relationship of the Denver beds to those of the Arapahoe series, 

 and the position of both with regard to the great fold are still more clearly 

 shown in the abandoned railroad cutting southwest of the Reform School 

 and 4")() yards south from the outcrop in Kinner Run. The cutting is in the 

 terrace, and shows in its western portion Arapahoe beds from the upper 

 part of the conglomeritic section, with very steep easterly dip. Succeeding 

 these is a gap corresponding to the clay strata of the upper Arapahoe, and 

 then brown and yellowish friable sandstones of the lower Denver formation, 

 the latter having a dip of 20° to 30 r eastward. The exact line between the 

 formations is not visible, hut can be located with sufficient accuracy from 

 the approximate thickness of the Arapahoe clays above the conglomerate. 

 It is here plain that the sharp bend in the fold, as expressed in the outcrops 

 of the present surface, occurs in the upper part of the Arapahoe series, and 

 the Denver strata are affected only in their lower members. 



From the Reform School southward to the base of Green Mountain 

 proper the dividing line between these two formations is necessarily drawn 

 with reference to the conglomerate horizon of the Arapahoe, as that alone 

 is well shown. Its strata can be traced for a mile or more, with a constant 



