360 



G. H. CHADWICK STEATIGRAPHY OF NEW YORK CLINTON 



latter will be the great unconformity whose eastern manifestation has 

 just been discnssed and whose western development has been traced by 

 Schuchert (12). jN'o comparable break is known to exist further up be- 

 tween the Niagara and Salina. Its character is strikingly exhibited in 

 the new barge canal rock-cut at Eochester, where, furthermore, there are 

 beneath it about 20 feet of beds at the top of the Eochester shale which 

 are apparently not present at Nia,aara and which are really a limestone, 

 being quarried and sold as such at the ^N'orth Goodman Street quarry in 

 Eochester (12 : 301) . These beds were noted by Hall (2 : 82) . On their 

 eroded upper surface rests the Decew (basal) member of the Lockport. 

 They are separated from the shale below by a perfectly clean-cut line, or 

 clay seam, and carry few fossils save Lingida lameUaia. It is proposed to 

 call this division the Gates limestone, from the town in which the beds 

 appear in the canal prism, and to restrict the term Eochester shale to its 

 proper expression as a fossiliferous calcareous shale below them. 



The full list of horizons^^ from the Gates down to the Cliamplainic 



(Ordovicic), with its major ( ) and minor ( ) disconformi- 



ties and the maximum kno"wn thicknesses in New York State, is : 



Upper Eontaric 



Feet 

 22. Gates limestone « 20 



21. Rochester shale 65 



20. Lakeport limestone 16 



19. Donnelly orec 2 



18. Phoenix shale and sand- 

 stone h 70 ? 



17. Kirkland ore and limestone. 6 



16. Brewerton shale 36 



15. Williamson shale 105 



Total 320 



Lower Eontaric. 



Feet 



14. Wolcott Furnace ore c 4 



13. Wolcott limestone 23 



12. Verona ore 5 



11. Sodus shale 69 



10. Sterling Station ore ly^ 



9. Reynales limestone 24 



(Dark shale in Lakeport well 7) 

 8. Furnace ville orec- 2^2 



7. Bear Creek shale and 



6. Martville sandstone fJ 10 



5. Maplewood shale c 21 



4. Thorold sandstone / 10 



3. Grimsby {Medina) sand- 

 stone V 60 



2. "Cataract" (Manitoulin) 



shale ^r (in New York) . . 29 

 1. Whirlpool sandstone 7( 22 



Total 281 



