PHYSICAL AND FAUNAL EVOLUTION 235 
series found directly overlying the fossiliferous marine Ordovicic 
of southern Pennsylvania, and generally classed by Pennsylvania 
geologists as “Oneida.” ‘This is a gray to white, rarely red, con- 
glomerate and quartz sandstone with rounded quartz pebbles and 
characterized by extensive cross-bedding. Its maximum thickness 
today is in Bald Eagle Mountain, near Tyrone City, Blair County, 
Pennsylvania, after which locality I originally named it.' This 
name, however, was preoccupied, and the formation under con- 
sideration is therefore called the Bald Eagle conglomerate, this 
ridge being due to the resistant character of this and the succeeding 
formation. At Tyrone the thickness is 1,319 feet, while thirty miles 
to the northeast, at the Bellefonte Gap, through the same ridge, the 
thickness is only 550 feet, and the formation is divisible into a lower 
hard gray sandstone without pebbles, 170 feet thick, and an upper 
greenish-gray somewhat ochery and micaceous sandstone with 
intercalated greenish shales. One hundred and sixty miles north- 
west from Tyrone, at Buffalo, this formation (Oswego sandstone) 
is 75 feet thick. It is here a white quartzite lying below the red 
Queenston shales, and represents only the upper layers of the 
gradually spreading fan of clastic sediments. In central New York 
the Oswego is 185 feet thick at the falls of the Salmon River. It 
there succeeds the Lorraine beds with perfect conformity, some 
Lorraine fossils extending into the lower Oswego. 
There can be little doubt that these beds represent the northern 
and western attenuated upper beds of the Bald Eagle conglomerate 
of Pennsylvania, unless indeed they belong to one or more distinct 
fans with a source in the north. 
The character of the rock, its cross-bedding, and absence of 
fossils indicate continental origin, and this is also shown by the 
nature of the overlap, which is that characteristic of river deposits. 
The intimate relationship between the Lorraine and the highest 
bed (Oswego sandstone) of this formation, indicates that the age 
of this formation is Lorraine. The Bald Eagle conglomerate is 
everywhere succeeded by the red shales and sandstones of the Juniata 
formation. In southern Pennsylvania this overlaps the preceding 
formation and rests directly upon the Eden sandstone. The forma- 
t Science, N. S., Vol. XXIX, p. 355. 
