SILICEOUS OOLITES AND OTHER CONCRETIONARY 
STRUCTURES IN THE VICINITY OF STATE 
COLLEGE, PENNSYLVANIA™ 
ELWOOD S. MOORE 
The Pennsylvania State College 
The town of State College is situated near the geographical 
center of Pennsylvania. It lies among the erosion remnants of the 
Appalachian Mountain system and near the western border, where 
the highly folded strata of the Tussey and Bald Eagle ranges begin 
to flatten out into the gently dipping beds of the Allegheny Moun- 
tains. These mountains occupy the synclines-of the original folds 
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Vertical Scale— 2 in. = 2,000 ft. Horizontal Scale— 4 in.=1 mile 
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Ed Ordovician Limestones Medina Conglomerate and Sandstone 
ES4 Transition Series Utica Shale 
Fic. 1.—Representative geological section through the odlitic area 
while the present valleys always lie along the original anticlines, 
which have suffered more rapid erosion than the synclines, permitting 
the streams to cut down to the base of the Ordovician system. 
A geological section through the area would show, from the oldest 
exposed strata upward, several hundred feet of interbedded sand- 
stone, limestone, and calcareous sandstone, grading over in the 
upper layers into limestone-conglomerate in which the pebbles 
« Paper read before Section C of the British Association for the Advancement of 
Science, Portsmouth meeting, t9t1. The discussion showed that siliceous odlites are 
plentiful in England in rocks of similar physical character and geological age, but 
such satisfactory evidence of their origin by replacement of calcareous odlites had not 
been previously found. 
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