PROCEEDINGS OF THE XI TIOXAL MVSEVM. 



VOL. XXX. 



CLASSIFICATION OF ORDOVTCIAN STRATA IN THE VICINITY OF 

 CINCINNATI, OHIO. 



Vai'iou.s classifications of the Cincinnati rocks have been proposed 

 from time to time, but reference to most of these is unnecessary, 

 especially since the sul)ject was ably discussed and reviewed by Nick- 

 les in 1902/' At that time this author indicated all of the divisions of 

 the Cincimiatian series, but applied names only to the various beds of 

 the Lorraine. In a subsequent paper'' he named the divisions of the 

 Richmond group. More recently Foerste ' has proposed several new 

 names as well as a few changes. 



The classification presented below is one now in preparation for 

 publication hy Mr. E. O. Ulrich of the U. S. Geological Survey and 

 the writer, and will ))e emploj^ed for mapping purposes in the Cincin- 

 nati area. As the })ublication of this article may be dekwed, departures 

 from the classifications of Nickles and Foerste, and the new" terms are 

 ])riefi3^ discussed below. The thickness of the various divisions is 

 indicated b}^ giving tlunr range in height al)ove low-water mark in 

 the Ohio River, starting at a point wdiere the lowest beds are exposed, 

 nameh', at West Covington, or at Bromlev, Kentucky, and suppos- 

 ing that the rocks ai'c horizontal. The heights mentioned are thus 

 only relative and this method is introduced here mainly because it was 

 employed by Mr. James and most of the other Cincinnati paleontolo- 

 sfists in locatino- the hoi'izon of their fossils. 



Richmond o;roii]i , 



O [('ovi Hilton srrotip 



Trenton 



Formation 

 (mapiil)le uniti-'). 



Members. 



Approxi- 

 mate height 

 in feet above 



low-water 



mark in Ohio 



River. 



fSaliula • 6(J.^-700 



Whitewater 625-665 



Liberty 590-625 



\\'aynesville 540-590 



Arnheini 460-540 



i ,Mt. All! )urn 425-460 



McMillan \ Corry villa 390-425 



iBellevue 375-390 



(Fairuiount 325-375 



llNIt. Hope 280-325 



Mc^Mieken 220-280 



100-220 



50-100 



45- 50 



30- 45 



l-\iirvie\v 



Kdeii <S()ntligate 



' Kconoiny . 



Utiea -. Fulton 



/Point l'lea«int 



■ iBromley 0-30 



«The (ieolojry of Cincinnati, .loin-. Cincinnati Sue. Nat. Hist., XX, 1902, jip. 

 49-101. 



''American (Geologist, XXXIi, 1*K«, j)].. 202-L'ls. 

 'Science, XXII, 1905, No. 5.53. pj.. 149-1.52. 



