NOMENCLATURE OF THE OHIO FORMATIONS 543 



The Clinton formation of Ohio is the lowest formation in that state, belonging 

 without question to the Upper Silurian. Between the Clinton of Ohio and the 

 upper fossiliferous beds of the Cincinnati formation occur in many parts of 

 the state a series of unfossiliferous beds which it is difficult to assign defi- 

 nitely either to the Upper or to the Lower Silurian. ' 



The fossils of the Belfast bed, as reported by Dr. Foerste, are 

 Haly sites catenulahis — a Clinton and Niagara coral not known in 

 the Cincinnatian series of Ohio, Indiana, or Kentucky ; annelid 

 teeth, which are identical specifically with forms found in 

 undoubted Lower Silurian limestones; and an Ortliis allied to 

 0. calligramma of the Clinton.^ 



27. By some geologists this system is called the "Ordovician," 

 a name introduced by Lapworth in 1879 for the Lower Silurian 

 of Murchison, which Sedgwick called " Upper Cambrian." This 

 usage, however, is strenuously opposed by the distinguished 

 British geologist, and former director-general of the Geological 

 Survey of Great Britain and Ireland, Sir Archibald Geikie, who 

 has written as follows : 



I consider that this proposal, which was honestly intended to obviate 

 confusion and to promote the progress of the science, is fair to neither of 

 these fathers of English geology, and is especially unjust to Murchison. 

 The division of "Lower Silurian" has the claim, not only of priority, but of 

 having been established and of having had its component members defined 

 by the author of the Silurian system in the early years of his investigation. 3 



When "Ordovician" is used in place of "Lower Silurian," 

 then the term "Silurian" is usually applied to the division which 

 Murchison named the "Upper Silurian." A very cogent reason 

 has been presented against this arrangement by Dr. William B. 

 Clark, who states : 



I prefer the use of Lower Silurian to Ordovician, as I do not think the 

 term Silurian of Murchison can with propriety be restricted to the Upper 

 Silurian. If the Upper and Lower Silurian are to be raised to period posi- 

 tion, and Ordovician used, I think some other name should be substituted for 

 Silurian.'* 



28. The mottled clays and thin arenaceous limestones which 

 outcrop in southwestern Ohio, and in the Ohio reports have gen- 



"■Jour. Cin. Soc. Nat. Hist., Vol. XVIII (1896), p. 163. 



^ Ibid., pp. 163, 165. 3 Text-Book of Geology, 3d ed., 1893, P- 73S- 



4J0UR. Geol., Vol. VI (1898), p. 342. 



