Tin- Ciriciunatian Series and its Brachiopods. 39 



the most pronounced limestone making age of the entire 

 Cincinnatian, the Liberty. This was characterized by an 

 abundance of brachiopods whose nearest relativ^es lived in 

 lormer limestone making epochs — Trenton and Maysville. 

 After 35 feet of calcareous material had accumulated, the 

 clear seas were suddenly terminated by a return to muddy 

 waters, and an extensive shoaling of the sea. It is probable 

 that at the time of the formation of the coral reefs of the 

 Sahida and the deposition of its coarse terrigenous sedi- 

 ments, a part of the Cincinnati anticline had emerged, and 

 that the shore features of the Saluda were caused by the 

 presence of this land. Some of the shaly strata of the 

 Saluda bear svin-cracks, showing that a part of the area 

 occupied by these rocks was occasionally even above the 

 surface of the sea. Terrigenous material was still supplied 

 during the deposition of the Whitewater and the Elkhorn, 

 but it was less coarse than that of the Saluda. At Madison, 

 Ind., the highest beds of the Richmond formation are 

 absent and the Clinton rests unconformably upon the lower 

 portion of the Whitewater. This shows that the area of 

 the land did not remain constant, but at times diminished 

 in size permitting the overlap of younger sediments. 



As has been indicated, the Richmond stage was a time 

 of epeirogenic movements in the eastern interior of the 

 continent. The sediments of the Medinan series of New 

 York indicate that this epoch was a time of epeirogenic 

 movements in the east. The Richmond is a formation 

 known only in the interior basin; the Aledina and Oneida 

 formations of the Medinan of New York are known only 

 in the Appalachian district. Both represent a time of 

 changing depths of seas, and shifting land masses. Because 

 of the peculiarities of their distribution, the movements 

 accompanying their deposition, and the character of their 

 sediments, a question has arisen as to the possible equivalence 

 of the Richmond and basal Medinan formations, and if 

 they are equivalent, to what system, the Ordovician or 



