TRIASSIC PORTION OF SHIN ARUM P GROUP 117 



crocodilian remains at Clay Hill, but, from the ensuing discussion, 

 it will seem not at all unlikely that such is the case. 



Newberry's Grand River section. — Where the Colorado begins, 

 at the junction of Grand and Green Rivers, about forty-five miles 

 northeast of the Henry Mountains, is one of the points cited by Button 

 at which the Shinarump Group is typically developed (see p. 103) and 

 where he says the Shinarump conglomerate is found in its character- 

 istic form. Aside from the very general statements of Powell (22) 

 I can find nothing in the literature of the Plateau Province recording 

 observations made at this locality. Button refers to Newberry's 

 description of the formations on Grand River some miles above the 

 junction with the Green. The vivid pen pictures of the scenery and 

 of the broader stratigraphic features given by this earlier explorer 

 of the region do indeed agree very well with those of Powell, but it 

 is difficult to recognize the Shinarump of Arizona in the section 

 Newberry gives of the possible Triassic beds. He found fossiliferous 

 Carboniferous strata (which Button and Powell considered as Aubrey) 

 in the Grand River Canyon where he descended to the stream,^ 

 and measured the superjacent section of red beds in " Canon Colo- 

 rado," the side gorge traversed in making the descent. This section 

 follows (20, p. 99): 



SECTION IN CANON COLORADO, UTAH (nEWBERRY) 



FEET 



9. Red and brown massive sandstone, fine-grained, not hard. No fossils 270 

 10. Soft red sandstone, in thin layers, separated by beds of red or dark 



brown shales .......... 350 



Greenish-gray micaceous conglomerate and gray sandstone, separated 



by red and purple shales ........ 92 



Soft liver-colored sandstones, becoming suddenly and locally nearly 

 white, with partings of shale ........ 350 



13. Brick-red massive calcareous sandstones, with some like the last. . 164 



As I have explained in the paper on a reconnaissance to Grand 

 River, at Moab (5, p. 644), the strata under No. 9 of Newberry's 

 section clearly belong to the lower part of the La Plata or White Cliff 



I Newberry believed that the side canon descended by him to Grand River was 

 but a few miles above the union with Green River. But it seems from most recent 

 maps that the "Canon Colorado," in which Newberry's route lay, enters Grand River 

 canon about twenty-four miles above Green River, and only about nine miles below 

 the present site of Moab. 



