THE BASIN PROVINCE 149 



In discussing other sections related to this, Gregory makes frequent 

 reference to "mud-lumps" and fragments of shale in the different layers. 

 He also speaks of the discontinuity of the layers (p. 27): "All the beds in 

 this section [2 miles east of Holbrook, Arizona] "decrease and increase within 

 short distances along their strike, and most of them retain their individuality 

 only for a few tens or a few hundreds of feet. It is difficult to locate equiva- 

 lent strata in two sections measured a mile apart." 



The beds are prevailingly quartz sands and the limestone present is in 

 lumps, grains, lenses, and concretionary layers. The gypsum is very largely 

 secondary in origin. 



(Page 30.) "The Moenkopi formation is assigned to the Permian (?) on 

 both stratigraphic and paleontologic evidence. It possesses essential unity in 

 structure, texture, color, composition, and conditions of sedimentation. An 

 erosional unconformity with the Kaibab limestone marks its lower limit in the 

 Little Colorado Valley of Arizona; and though clear evidence of such relation 

 has not been obtained in the San Juan region, the fossiliferous Goodridge beds 

 are separated from the Moenkopi by a sharp lithologic break. The Shinarump 

 conglomerate (Triassic) unconformably overlies the Moenkopi or the DeChelly 

 sandstone, which is also assigned to the Permian(?). The paleontologic evidence 

 obtained both within the Navajo Reservation and along its borders is conflicting. 

 Fossils collected on the rim of the Little Colorado Canyon by Mr. Pogue include 

 many fragmentary bivalves and some gastropods. Professor Schuchert reports: 



" ' I see Bakeivellia, Pinna, Schizodus, and Bellerophon. The horizon is clearly 

 above the Pennsylvanic and is the Permic molluscan fauna devoid of brachio- 

 pods. The horizon may be high in the Permic, that is, above Lower Permic, as 

 the term is understood in America, say about Middle Permic' 



"Fragmentary plant remains, including species of Walchia, were collected at 

 a number of localities and in 1913 E. C. Case and W. B. Emery, of my party, 

 obtained determinable plant fossils from the middle Moenkopi beds 3 miles west 

 of Fort Defiance. Regarding this collection David White writes: 



"'The large fragment with closely placed lateral twigs belongs to another 

 Walchia resembling Walchia hypnoides. It is perhaps identical with that de- 

 scribed by Dawson as Walchia gracilis. One or two small fragments in one of the 

 loose rock pieces agrees still more closely with Walchia gracilis. These forms of 

 Walchia are characteristic of the Permian and are present in Oklahoma and in 

 the Wichita formation of Texas.'" 



The beds of the Kanab Valley described as Permian by Walcott seem 

 now to be very definitely assignable to the Triassic (Meekoceras beds) and 

 equivalent to the Permo-Carboniferous of the Uintah Mountains. 



(Page 31.) "On the northern flanks of the Zuiii Mountains, near Fort 

 Wingate, Dutton found 'several specimens of Bakeivellia and an attenuated form 

 of Myalina corresponding to the forms of the latter genus which are common 

 in the Permian.' The description of the strata from which these fossils were 

 obtained indicates their equivalency with the Moenkopi at Fort Defiance and 

 elsewhere. S. W. Williston states that 'there are genuine Permian red beds' in 

 the Zuni Mountains and that 'a Paleozoic brachiopod was obtained by Mr. 

 Miller in the (Moenkopi) cliffs at Holbrook.' 



