222 E. M. KINDLE 
as Cape Lisburne, on the Arctic coast,’ and it occurs at numerous 
points on the Yukon and Porcupine Rivers in eastern Alaska. 
Concerning the interval between the Upper and Lower Carbon- 
iferous faunas in this region we have but few data. No fauna repre- 
senting it has been found. 
The younger of the two Carboniferous faunas of southeastern 
Alaska is well represented in the limestones about Pybus Bay, on the 
southeast side of Admiralty Island (7), where they outcrop exten- 
sively along both arms of the bay. The limestones characterized by 
this Upper Carboniferous fauna have a thickness of about 600 feet 
at Pybus Bay. These Upper Carboniferous limestones are generally 
heavy-bedded or massive, as shown in the photograph (Fig. 2). The 
Lower Carboniferous limestones where observed have thinner bed- 
ding and are darker-colored than those of the higher horizon. 
The following section, taken along the west shore of the east arm 
of the bay, indicates the character of the Carboniferous limestone (c 
of the section), and the associated beds: 
Feet 
g. Black to dark-gray gait Slates, 9, Resse ae on ene se eee OO 
j. «Covered interval | 2° 72. LOO 
e. Massive or heavy-bedded, gray tracstone man conchoidal feerure LAO 
d. Light-gray limestone full of small, angular, cherty masses. . . . 80 
c. Light-gray cherty limestone in 10” to 30” bands, fossils abundant . . 600 
b. Red chert in 6” to 20” bands .°. . . 300 
a. Black chert in 4” to 10” bands, with rarely a aurowe or feat bande 2125550 
1,970 
The Mesozoic beds are represented by the two divisions e and g 
of the section. Whether the shales and the Mesozoic limestone are 
conformable or not, the section does not show, but the latter and the 
Carboniferous limestone are unconformable. The total thickness 
of the black slates cannot be determined from the outcrops which 
continue beyond the end of this section, since they belong to a series 
of low folds which do not bring the entire thickness of the beds to 
view. Other outcrops, however, just outside the bay indicate a total 
thickness of not less than goo feet for these black slates, which have 
been referred provisionally to the Lower Cretaceous by Dr. Stanton, 
on account of the occurrence in them of a Cretaceous type of Aucella. 
t Bulletin No. 278, U.S. Geological Survey, pp. 22-25. 
