TRIASSIC PORTION OF SHINARUMP GROUP 109 



interfering as it does with the harmony of broad architectural features 

 and stratigraphic geology shown elsewhere in the section, leads 

 Button to humorously complain that, "Somehow we cannot help 

 thinking that the conglomerate has no business there, and that it 

 ought to have been cut off at the base of the Vermilion Cliffs, or else 

 it ought to be relegated to the Permian (7, p. 45)." 



Button found, and specially notes, the erosional unconformity 

 below the Shinarump conglomerate at Pipe Spring, a few miles west 

 of the Kanab Valley (7, p. 80), and in discussing various unconformi- 

 ties by erosion noticeable in the Plateau district says: "Perhaps the 

 most widely spread occurrence of this kind is the contact of the sum- 

 mit of the Permian with the Shinarump conglomerate which forms 

 the base of the Trias. Wherever this horizon is exposed, this uncon- 

 formity is generally manifest" (7, p. 211). 



As to the character of the Shinarump conglomerate Button adds 

 little, in the publication under review, to the earlier statements. 

 His general characterization of it is as "a light-brown, coarse sand- 

 stone, here and there passing into a conglomerate" (7, p. 17). There 

 never seems to be any question as to the ability to recognize the 

 conglomerate horizon, with Button or other early observers. Com- 

 menting on the uniformity of strata of the whole Plateau section. 

 Button remarks that: "The curious Shinarump conglomerate is the 

 same in Pine Valley Mountains (near St. George), in the terrace at 

 Kanab, at the base of the Echo Cliffs, and in the land of the Standing 

 Rocks" (7, p. 208). The last-named locality is about the junction of 

 the Grand and Green rivers. 



On the geological map accompanying this monograph Button 

 distinguishes the Permian from the Trias, and represents both 

 extending south along the eastern side of the Little Colorado 

 Valley. 



The Shinarump of Little Colorado Valley. — All students of the 

 northern and eastern borders of the Colorado Plateau agree in the 

 general view expressed by Button on his map that the various for- 

 mations or groups between the Aubrey and the base of the Cretaceous 

 cross the Colorado Canyon near the mouth of the Paria River, and 

 that their outcrops extend thence southeasterly on the northeast side 

 of the Little Colorado Valley. From the statements of Marvine 



