472 H. W. SHIMER PERMO-TRIASSIC OF ^s^OETHAVESTERX ARIZONA 



IXTRODUCTIOX 



Four months' field work in Xew Mexico and Arizona, in 1906,^ resulted 

 in numerous geologic sections and fossil collections. Some of these 

 results have been published.^ 



The present paper presents some Upper Permian and Lower Triassic ? 

 sections, with their faunas as represented in our collections. The faunas 

 are mainly from the upper Kaibab and lower Moenkopi formations. 



Xorthern Arizona represents an old peneplained surface, developed 

 with a slope to the south, which was raised into a plateau during the 

 Pliocene. Since that time the softer Triassic ? shales have been largely 

 eroded, leaving exposed the hard, siliceous Upper Permian (Kaibab) 

 limestones. This erosion brought into relief old fault lines, and, with the 

 aid of subsequent faulting along some old and many new lines, has pro- 

 duced the present topography. These strata, very nearly horizontal, have 

 usually a gentle dip to the north: this is true from the southern edge 

 of the plateau, the Mogollon Eim, to the Utah border where they dip 

 beneath the later Mesozoic and Cenozoic beds. 



Table of For^iatioxs 



Triassic 



Upper 



Lower 



I Cliiule 



i Shinarump conglomerate 

 Moenkopi ? 



Discoiiformity 

 Discoiiformitv 



Permian 



Kaibab 

 Coconino 

 ; Supai (upper) 



Disconformity 



Pennsylvanian 



Supai (middle and lower) 



Disconformit\- 



Mississippian (Lower) Redwall 



- lu a party under the most efficient leadership of Prof. Douglas W. Johnson, of Coluin 

 bia University. 



3 The stratigraphy of the Mount Taylor region. New Mexico. Am. .Jour. Sci.. 4th ser., 

 vol. 25. 1908, pp. 53-67. 



The lithologic section of Walnut Canyon. Arizona, with relation to the cliff-dwellings 

 of this and other regions of northwestern Arizona. Am. Anthropologist vol 1"^ 1910 

 pp. 237-249. 



The small cave houses of Arizona. Science Conspectus, vol. 2, 1911. pp. 16-18. 



