“ANTONIO ALZATE.” 33% 

rests upon the uptruned edges of the slates and abuts against the Es- 
camela limestones. The conglomerate is coarse and has been formed by 
the braking down of the limestones. The only rock I observed in the 
conglomerate is the limestone and black or dark colored chert of the 
same group. 
Just beyond San Miguel Totolapa a small anticlinal occurs which 1 
have consider as belonging to the lower Gretaceous. The rock is thinly 
bedded sandstone with shaly partings and of a yellowish color, proba- 
bly from the oxidation of the pyrite of iron. 
There is quite a lithological resemblance in this formation to that 
which occurs near Coyuca, which is 50 kilometers further down the 
river valley. 
Immediately following this small anticlinal the Miocene breccia is 
encountered and extends to Ajuchitlan, a distance of 14 kilometers 
down the river. A part from general section from Iguala to San Miguel 
Totolapa, 1 will include a few sections taken at various points and 
which will be of interest as bearing upon the general geology of the 
region, í 
Section No. 1 is taken from Ajuchitlan to Tinoco mountain. Ajuchi- 
tlan is 375 kilometers from Mexico along the line of the rail road sur- 
. vey and river. 
Section No. 2. From Coyuca to Placeres, Coyuca is 230 kilometers 
from Mexico by R. R. survey. 
Section No. 3. Extends from the town to Pungarabato, just North ot 
Coyuca to the northwestward to Huetamo. 
Section No. 4. From Santiago located 16 k. below Zirándaro (475 
from Mexico City by R.R. survey) northward to Espíritu Santo mines. 
Section No. 5. Appearance of Pliocene Breccia opposite Cuicuipajio 
(about 550 k. from Mexico City by R. R. survey). 
Section Miocene. The same breccia which forms the Aguila and 
Nanchi mountain is that which is encountered in the Tinoco mountain 
and the same as that of the Balsas river valley opposite San Miguel 
