NOTES AND SKETCHES BY VISITING GEOLOGISTS. 



NOTE ON WALNUT CANYON AND ITS CLIFF DWELLINGS. 

 By Prof. T. McK. HUGHBS. 



Fio. 30.— Clifl" dwellings in Walnut canyon. 



Walnut canyon, 8 miles (12 km.) southeast from Flagstaff, Ariz., 

 is a dry canyon in summer, but after the rains the channel is a roaring 

 torrent. It is cut to a depth of 250 feet (85 m.) in the Aubrey or Upper 

 Carboniferous rocks, which yielded to our party two species of Produo- 

 tus and some mytiloid lamellibranchs. The lower half (Fig. 31-2) con- 

 sists of false-bedded sandstones of very uniform character, the breadth 

 of the bands picked out by the principal divisional planes, whether of 

 bedding or cross-bedding, being approximately the same from top to 

 bottom, and the Hat clean-cut wall showing no evidence of alternations 

 ofharder and softer beds. Not so the upper half of the side of the gorge, 

 which consists of irregular beds of limestone, some of which protrude in 

 ledges of varying thickness, while others have flaked off under the 

 influence of the weather and receded into continuous rock-shelters, 

 like those in the mountain limestone along the vale of Clwyd in North 



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