Name:  Siliceous Oolite

Geologic Name:  Gatesburg

Reference:  Butts, Charles, Swartz, F.M., and Willard, Bradford, Atlas
of Pennsylvania, No. 96, Tyrone Quadrangle, p. 10-12, 1939.

Microscopic characters:  The circular oolites have a single grain of
a granular aggregate of quaratz grains in the center.  Surrounding
this there are two or three zones of much finer grained material. 
The grain size varies in the different zones.  The cement is
granular quartz that shows considerable variation in grain size.