DENVER OF GEEEX MOUNTAIN. ] 75 



base ami represents the change from the friable semi-clayey rocks of A to 

 the distinct conglomerate. Veinlets in this sand rock are usually filled by 

 zeolite or calcite and the actual cement is doubtless of the same substances. 



Division c, 285 feet. — The strata included under C are probably very much 

 like those of Division A, but they are much better exposed than the former 

 011 the line of profile. The three divisions (A, 15, and C) really constitute 

 a single division standing in contrast to the strata above. 



Nearly the entire thickness of C is made tip of yellowish-brown sands 

 and clays with intermediate members. The little ravine coming from the 

 hollow in the face of the mountain above exposes nearly the entire thick- 

 ness in a most excellent manner. Few horizons stand out so plainly that 

 they can be specially designated. Immediately above the conglomerate <>i' 

 B come about 30 feet of pure sandy strata; there is then a layer of pebbles 

 4 inches thick, succeeded by yellowish-brown clays containing varying 

 amount of sand. The small conglomerate layer is frequently broken up 

 into a series of lenticular masses arranged one after another. At about 100 

 feet above B is a development of G to 8 feet of dark, sandy clays with 

 light spots very similar to certain layers noticed in the section at the 

 northeast point of South Table Mountain. Above this comes a crumbling 

 semiconglomerate or gravel layer 3 feet thick. This stratum has a strike 

 N. 15° 30' W. and a dip of 42° easterly. Only eruptive material was 

 noticed in this conglomerate. This lied is followed by fine, yellowish, sandy 

 beds, soon passing into clays of buff, lavender, and dark-brown colors, also 

 somewhat arenaceous. Some of the dark-brown clays are mottled by 

 light spots, as in the stratum already mentioned. In such clays occur 

 concretionary masses of hardened, light-colored clay with an outer zone of 

 darker material in which a rude cone-in-cone structure is visible, the 

 apices pointing inward. These masses are ellipsoidal and up to 2 feet in 

 diameter. Search for fossils in them proved fruitless. These concretions 

 are apparently not confined to particular layers, but may be found 

 anywhere in clay beds of the character mentioned. 



The upper portion of Division C is composed chiefly of friable sand 

 rock with clay, and it is not so continuously exposed as are the lower 

 nortions. 



