CONTENTS 



Pages 



Diastrophic Importance of the Unconformity at the Base of the Berea 



Grit m Ohio. By H. P. Gushing 205-216 



Origin of the Red Beds of Western Wyoming. By E. B. Branson 21 7-230 



Origin of Thick Gypsum and Salt Deposits. By E. B. Branson - 231-242 



Length and Character of the Earliest Inter-Glacial Period. By 



A.P.Coleman - 243-254 



Obsidian from Hrafntinnuhryggur, Iceland : Its Lithophysae and Sur- 

 face Markings. By Fred. E. Wright 255-286 



Post-Ordovician Deformation in the Saint Lawrence Valley, New 



York. By George H. Chadwick 287-294 



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