7o6 JAMES H. GARDNER 



are soft and of mixed black and dark-green colors near the locality in question, 

 and capped by light and yellowish sandstones. These are the lowest beds of 

 the Eocene, and I traced them for forty miles to the south along the belt of country 

 intervening between Cretaceous No. 4 ["Laramie"] and the reddish sandstone 

 [Wasatch]. At the locality just mentioned they conform to the sandstones above, 

 having a dip of 10° southwest, while they do not conform to the hog-back of 

 Cretaceous No. 4 ["Laramie"], the nearest available outcrop, which dips at 

 25° west. Farther south this marl is represented by low hills of generally lighter 

 color. Near Nacimiento it has an increased importance, as it rises both to the 

 east and south. The valley of the Upper Puerco is excavated in it for some 

 distance, and its blackish, greenish, and gray hills are seen on both sides of the 

 river. At a point on the river about six miles below the village of Nacimiento, 

 the lower sandstone of the Eocene forms a perpendicular bluff, which terminates 

 in an escarpment of 500 feet elevation facing the south. The red-striped marls 

 [Wasatch], having acquired a gentle northern dip, disappear from view some 

 miles to the north, and the termination of the underlying sandstones warned us 

 that we were approaching the southern border of the basin. 



The border of the sandstone turned to the west at this point, the line of 

 bluffs continuing as far as vision extended. Below and south of it, the varied 

 green and gray marls formed the material of the country, forming badland tracts 

 of considerable extent and utter barrenness. They formed conical hills and 

 flat meadows, intersected by deep arroyos, whose perpendicular walls constituted 

 a great impediment to our progress. During the days of my examination of 

 the region, heavy showers of rain fell, filling the arroyos with rushing torrents, 

 and presenting a peculiar character of this marl when wet. It became slippery, 

 resembling soap in consistence, so that the hills were climbed with great difficulty, 

 and on the levels the horses' feet sank at every step. The material is so easily 

 transported that the drainage-channels are cut to a great depth, and the Puerco 

 River becomes the receptacle of great quantities of slimy -looking mud. Its 

 unctuous appearance resembles strongly soft-soap, hence the name Puerco, 

 muddy. These soft marls cover a belt of some miles in width, and continue at 

 the foot of another line of sandstone bluffs, which bound the immediate valley 

 of the Puerco to a point eighteen miles below Nacimiento. Here the sandstone 

 again turns to the westward presenting a southern escarpment of 500 to 1,000 feet 

 elevation. I could not be sure whether this sandstone is identical with that of 

 the escarpment twelve miles north, but suspected it to be such. [It is a lower 

 sandstone and is Mesaverde.] Immediately south of it, low hills of Cretaceous 

 No. 4 ( ?) [Mancos] extend across the Puerco [River] and continue south of the 

 Eocene (?) bluflfs at a distance of a mile or two with a western strike. They 

 were as elsewhere of a soft yellowish sand and clay, including shale beds, and 

 contained abundance of Inoceramus, like those found on the Gallinas. 



Ten miles t<' the southward, the underlying Cretaceous beds are capped by 

 a horizontal table of basalt (Mount Taylor flow) thus forming a mesa, through 

 which the Puerco passed in a canon. I supposed this to be the forerunner of 



