20 NEW YORK STATE MUSEUM 



Niagara river. The Clinton strata are exposed within the 

 Niagara gorge all the way from the falls to Lewiston at the north 

 end. They are overlain by 70 feet of Rochester shale and rest upon 

 the "gray band" that forms the uppermost layer of the Medina.^ 

 Their aggregate thickness is 32 feet. 



STRATA FEET 



Bluish gray limestone, somewhat crystalline, fossiliferous. 12 

 Compact limestone, few fossils, carries iron pyrite in 

 lower portion, the only semblance of the iron ore seams 



farther east 14 



Bright green and olive shale 6 



Rochester. Between Niagara river and Rochester, a distance 

 of 75 miles, no complete sections of the Clinton are available. At 

 Rochester the Genesee river cuts through the entire formation, af- 

 fording one of the best exposures along the entire belt. 



STRATA FEET 



Bluish gray limestone (Irondequoit), crystalline, abun- 

 dant fossils in certain parts . 18 



Green shale (Williamson) with dark bands containing 

 graptolites and pearly bands near top with A n o p 1 o - 

 theca hemispherica 24 



Hard limestone (Wolcott), silicious, holding Pentam- 

 erus oblongus, commonly known as Pentam- 

 erus limestone 14 



Iron ore (Furnaceville), fossil hematite 14 in. 



Green shale (Sodus), few fossils 24 



The formation is here 81 feet thick, a gain of 49 feet over the 

 thickness shown at Niagara Falls, mostly represented in the shale 

 members [see pi. 2]. 



Ontario, Wayne co. From the mine workings and drill holes 

 near Ontario, 15 miles northeast of Rochester, the following suc- 

 cession has been established for the lower members of the for- 

 mation. 



STRATA FEET 



Soil and gravel 10+^ 



Shale (Williamson) grading into limestone below 2 



^For fuller description of the Niagara Falls section, Grabau, N. Y. State Mus. 



Bui. 45. 1901. 



