I32 NEW YORK STATE MUSEUM 



described and figured the following Guelph forms: Trematonotus 

 alpheus (Genoa and Springfield), Straparollus niagarensis 

 (Cedarville), Trochonema pauper (Greenville), Cyrtoceras her- 

 zeri (Cedarville), C. my rice (Yellow Springs), Phragmoceras par- 

 v u m (Cedarville). 

 Newberry 1 says : 



In the northern part of the state the best exposures of the Niagara are 

 at Geneva, Elmore and Washington. . . In all this region only the upper 

 part of the Niagara is seen, the equivalent of the Guelph limestone of 

 Canada. . . This portion of the formation is a rough, cellular, cream 

 colored magnesian limestone sometimes mistaken for sandstone, yet being 

 nearly a typical dolomite in composition. . . The cells and cavities which 

 are so characteristic of this rock are usually produced through the removal, 

 by solution, of the shells, of which it once contained great numbers; hence 

 all its fossils are represented by casts only. 



Among the fossils of the Niagara [Guelph] group which occur most 

 abundantly in northern Ohio, may be mentioned Megalomus cana- 

 densis, Tremanotus alpheus, Pleurotomaria solarioides, 

 Murchisonia macrospira, Trimerella ohioensis, Penta- 

 merus occidentalis, Cypricardites? quadrilatera, Favo- 

 sites niagarensis, Obolus conradi, etc. 



In the southwestern portion of the state one of the best sections is 



found at Hillsboro and was thus determined by Edward Orton. 2 



FEKT 



i Hillsboro sandstone 30 



2 Guelph, Cedarville or Pentamerus limestone - - 20 



3 Upper or Springfield cliff 45 



4 Lower or West Union cliff 45 



5 Niagara shales 60 



6 Dayton limestone 5 



Newberry says of this : "The upper limestone of the Hillsboro section 

 is evidently the equivalent of that exposed at Geneva, Elmore, etc., and 

 like that, represents the Guelph division of the Niagara. It contains 

 nearly the same fossils at Hillsboro as at Geneva . . . but Pentamerus 



■Geol. Ohio. 1873. 1:129. 



2 Report of Progress for 1870, p. 301. 



