NEW YORK STATE MUSEUM 



The formations involved are as follows in desi ending order: 



ERA OR 

 RYS1 l \l 



I' I RIOD OR 



, n p 



\ . , l OR 



Cayugan Salina 



( mtaric 



or 



Upper Silurii 



tran 



Oswegan 



Niagara 



Clinton 



Medina 



I m I ^MENTATION 



R] PR1 5EN Ml) IN CO! 

 ON I 111. MAP 



I Bertie waterlime 

 I ( '.iiniilus shale 

 j Vernon shale 

 I Pittsford shale 

 { Lockport dolomites with 

 interbedded Guelph 

 ! faunas 



| I m< kport dolomites 



I Rochester shale 



{ [rondequoit limestone 



| Williamson shale 



< Wolcott limestone 



[ Furnaceville ore 



I Sodus shale 



f Upper Medina (sand* 



\ stones and shales) 



I I ,ower Medina (shales) 



Sequence of events preceding the deposition of the rocks of the 



Rochester area 



Although the Medina is the lowest formation that is exposed in 

 western New York, well records have shown that we have the com- 

 plete older series as known in the Mohawk valley, around the south- 

 east border of the Adirondacks and in Canada. 



The following table gives the order of succession of the rocks of 

 the Rochester region belo.w the Ontaric or Upper Siluric as deter- 

 mined from well records. 



IK a OR 

 SYSTEM 



Champlainic or 



Lower Siluric 



Cambric or 

 I onic 

 Archean . . . 



PERIOD OR 

 GROUP 



Cincinnatian 



Mohawkian 



Canadian 



Saratogan 



\*,l OR 

 SI \<.l 



j Lorraine beds ) 

 ( Utica shale f 



f Trenton limestone 1 m 



-( Black River limestone ;- 



I a ville limestone J 



lieekmantown dolomite 



( Little Falls dolomite) 

 IN itsdam 



TIIICKM SS 

 IN I I I I ■ 



954 



'37 



(?) 



3 + 



1692 + 



hild, HI I Aca Sci. Pi 1,1.1: 184. I is t me evidence indicating 



the prcsctiei ji;. 



