THE OLDER MESOZOIC OF ARIZONA. 



39 



Description of the section shovm in jig. 2. 



1 . Carboniferous limestone - 100 



2. Moencopie formation - - - 600 



3. Lithodendron member - 500 



4. Variegated marls — - - - 400 



5. Limestones and mortar beds - - 200 



6. Variegated sandstones - 500 



7. Brown sandstones - 600 



S. White sandstones - 100 



Total thickness - - 3, 000 



The brown sandstones, No. 7, are here abnor- 

 mally thickened at the expense of the variegated 

 sandstones, No. 6. This may be due to the south- 

 ward extension of the Echo Cliffs displacement, and 

 a dike less than 2 feet thick and nearly vertical 

 was seen on the south side of the valley running 

 through the entire bluff' and trending southwest 

 almost exactly in line with Echo Cliffs. 



SECTION in.— THE LOWER LITTLE COLORADO VALLEY. 



g i/ 



Limestone Canyon 

 Little Colorado Valley 



about 7 miles, and following it at that level for about 6 miles more, to 



where there is a decided bend in the stream which comes in from the east. 



The Moencopie here runs between high bluffs, and 



the section shows those of the right bank, passing 



through Tuba, which is 300 feet above the bed of 



the Moencopie, and continuing on over the brown 



and white rocks. The maximum thickness is 3,000 



feet and the length of the section 24 miles. The 



following is the section: 



Painted Desert 



[PL IV, E-F.] 



This section aims to give the entire series from 

 its contact with the Paleozoic near Black Tank, at 

 the foot of San Francisco Mountain, to the highest 

 beds reached on the mesas that rise to the south of 

 the Moencopie Wash. It passes through the bed 

 of the Little Colorado a few miles above Tanners 

 Crossing and the important marl butte region to the 

 east of the river, in which most of our work was done, and passes over the 

 high escarpment 10 miles farther east, terminating in the white sandstones. 



