STRATIGRAPHY OF SHAN-TUNG. 25 
The basal layers of the Man-t’o are usually soft, white, or yellowish 
clays of fine texture, which, even at the contact with the Pre-Cambrian, 
contain no appreciable amount of conglomerate or arkose. The lower 
portion of the Man-t’o, for about 60 meters above the base, consists of pale, 
earthy limestones and varicolored shales, alternating in layers 15 centimeters 
to 9 meters thick. Among the more continuous beds are two buff-gray 
argillaceous limestones, one about 3 meters thick overlying the basal clays, 
the other varying from 3 to 9 meters in thickness and situated 36 meters 
above the first. Each of these limestones produces a prominent ledge in 
the slopes where they are exposed. ‘The associated shales are variable 

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Fic. 6 (Blackwelder) —Ch’ang-hia, Shan-tung. Section of Cambrian strata in the north side of Man-t’o 
butte. 31= red granite; 2= soft yellow shales; 3= buff earthy limestone; 4= gray and buff calca- 
reous shales; 5=syenite-porphyry sheet; 6= greenish shale; 7= earthy limestone; 8 = maroon 
shale; 9 = buff earthy limestone; 10= white calcareous shale; 11 = red shale; 12= olive gray lime- 
stone; 13 = dark shales; 14= gray limestone; 15 = maroon shale; 16= gray limestone; 17 = brown 
and gray shales; 18 = gray limestone; 19 = brown shale; 20= thin-bedded, dark oolite and greenish 
shale; 21= gray limestone with black oolitic bodies. The scale of thickness is indicated in feet. 
when traced horizontally. Most of the layers are gray or buffish, and they 
often approach slaty limestones in character. Very thin beds of soft 
green, yellow, and maroon shales are, however, almost always present. 
The next 36 meters consist largely of reddish, maroon, and yellow shales 
which are decidedly variable. Within these are two thin layers of lime- 
stone, which are gray and crystalline on fresh surfaces, but become olive 
or russet on weathered exteriors. Most of the sections show also a shaly 
red sandstone, 5 or 6 meters thick, at the top of the 36 meters mentioned. 
The remainder of the Man-t’o is fairly constant in its characteristics. It 
consists largely of dark shales of brown, maroon, and purplish tints. They 
are often sandyand micaceous. Gray crystalline limestone occurs in layers 
2 centimeters to 1.5 meters thick, and also in lenticular nodules embedded 
in the dark shales. Two of the limestone beds are fairly continuous, 
