Geology of Ft. Apache Region, Ariz. — Reagan. 275 
Section xii. North from near Camp Apache (Fort Apache) 
(Gilbert, U. S. Geographical Survey west of the 100th Meridian, 
Vol. Ill, p. 165.) 
Quaternary: feet 
1. Basalt and basalt gravel 70 
2. Pale pink slightly coherent, massive sand and gravel resting 
unconformably on No. 3 520 
Anbery Group: 
3. Calcareous sandstone : 
a. yellow 100 
b. red 180 
4. Soft red and gray shales, interrupted by sectile limestone : 
a unseen ; shale ? 190 
b. soft red shale 50 
c. gray limestone 10 
d. gray shale 10 
e. yellow limestone 4 
f. red and gray shales 60 
g. gray to cream limestone, with minute fossils 25 
h. red shale 80 
Upper Red Wall Group: 
5. Fossiliferous gray limestone : 
a. thick bedded limestone 25 
b. unseen ; red shale (?) 25 
c. limestone, sectile to massive, with some chert (Produc- 
tus, Bellerophon, Spirifer, Archaeocidaris 75 
6. Red gypsiferous shales, with sandstone and limestone : 
a. unseen ; shale ( ?) 160 
b. cream gray thin-beded limestone 15 
c. unseen ; shale (?) 85 
d. green gray impure limestone 15 
e. red gypsiferous shale 70 
f. massive gypsum 10 
g. red shale, graduating below to soft red sandstone 240 
h. red and gray shale interlaminated with gypsum 70 
i. calcareous sandstone with prints of mud-cracks 1 
j. red shaly, ripple-marked sandstone, with red-clay shale 
and red sandy shale 120 
k. unseen : shale (?) 50 
Total *226o 
STRATIGRAPHY. 
The Archaean. — Archaean rocks form the nuclei and also the 
crests, and in many places the flanks, of the Pinal and Apache 
mountains. They are also exposed in many places around the 
Plateau break. They are the country rocks of lower Canyon 
*The age of the cocks given above Is Inserted by the writer 
