172 The American Geologist. Mayc\i, loos. 
more fully described by Grabau" under tlie term "Rondout 
waterlime." From this description we learn that the Bertie 
formation is about fift}^ feet thick and consists of magnesian 
limestones and shales, grading downward into the Salina gyp- 
siferous shales, the latter having here a thickness of about 380 
feet Above the Bertie cement rock and not sharply separated 
from it, is the Manlius limestone, locally known as the "Bull- 
head rock." It is seven to eight feet thick and is a mottled dolo- 
mitic compact semicry stall ine limestone "having frequently the 
appearance of a limestone breccia." The fauna of the "Bull- 
head rock" described by Grabauf is unmistakably that of the 
Lower Manlius, or the Cobleskill member. Upon the Manlius 
of this region there was deposited a part of the Upper Oris- 
kany, but nearly all of it was removed by erosion before the 
introduction of the Onondaga limestone. Parts of this sand- 
stone are still preserved in the joints and cavities of the Lower 
Manlius. Unconformably upon the Manlius rests the Onon- 
daga cherty limestone abounding in corals of Middle Devonic 
age. 
In the southern half of the Appalachian legidn, the Bertie 
formation is not lithologically distinguishable from the Salina, 
and here the latter term is extended to embrace the entire in- 
terval between the Niagara and Manlius. 
HELDERBERGIAN SECTIONS.J 
Section nt Indian Ladder, Albany County, N. Y. 
Marcelhis, Onondaga limestone, 85 ft. Schoharie grit, 3 ft. Esopus 
shale, 100 to 120 ft. Upper Oriskany, i ft. Hiatus. New Scotland and 
Becraft, 160 ft. Coeymans, 52 ft. 
Manlius, 50 ft. 
Transitional Manlius (14' 6"). Has no T. gyracanthus but 
Spirifer vannxeisti occurs throughout. 
Thin bedded Manlius (31' 6"). Has an abundance of T. gyra- 
canthus, S. vanuxemi, Leperditia alta, etc. 
Waterlime or Rondout (4' 6") resting unconformably on the 
Frankfort shales of the Champlainic. 
Not far away to the north, at Altamont, on the Frankfort rest 
dark-gray, thin-bedded limestones less than 2 ft. thick. These 
* Bull. N. Y. state Mus., ix, No. 45, 1901, pp. 115-117. 
t Bull. Geol. Soc. Amer., xi, 1900, p. 350. 
t These sections and many more extending from Pennsylvania south to 
Tennessee will be published elsewhere in greater detail and will be the basis for 
a general discussion of the sequence of events in the Cumberland Mediterraneau 
throughout Ontaric and Devonic time. This work is now nearly completed. 
