NEW YORK STATE MUSEUM 



tion here afforded, though the unfavorable exposure may still veil its 

 presence, but we are satisfied that the careful analysis of this section 

 recently made by Mr Luther locates with precision the horizon which at 

 Shelby so much more favorably expresses its contents. To elucidate these 

 stratigraphic relations we here give the detailed section of the dolomites 

 presented in the cut of the Gorge Railway, y z mile north of the east end of 

 the bridge, supplemented at the top by a temporary exposure made by the 

 Ontario Power Co. on the Canada side. 



Brown dolomites exposed at Goat island and Three Sisters islands 

 with summit near head of rapids. Full of cavities and with 

 Stromatopora, Halysites. Weathers very scraggy. Uppermost 

 bed (4') sandy 



Car barn of Gorge Railway ; not exposed 



Brown, thin bedded dolomites with rough surface and black partings 

 Thin bedded dolomite, fine grained and very hard. Continuous bed 

 of chert nodules near top ; probable horizon of upper Shelby fauna 



25' 



10' 



8' 



1 2' 6" 



19' 



1/6" 



28' 



Compact drab dolomite; few cavities. Horizon of lower Shelby 

 dolomite near top 



Smooth, thin bedded dolomites with Stromatopora ; at top, Enter- 

 olasma, Favosites 



Compact light brown dolomite 



Rochester shale 



The basal layer of the series (i) is quite homogeneous, though the 

 lower part is schistose. The same stratum is seen at Lockport along the 

 banks of the canal beginning a little west of the locks in the city and 

 extending continuously toward the southwest for a mile. Farther west 

 near Gasport it is quarried at the top of the banks of the ravine south of 



