358 G. H. CHADAVICK STRATIGRAPHY OF NEW YORK CLINTON 



Otsquago-Bear Creek), another faint compression that converted the ero- 

 sion-weakened crest of the previous arch into a double anticline before 

 the Reynales limestone was deposited. Less evident from the diagram is 

 an overlap relation of the Thorold-Maplewood on the red Medina, which 

 would be more easily demonstrated had the wells penetrated deeper. 

 These diagrams indicate the following ''order of events'' : 



(1) Post-Ordovician erosional unconformity and transgression. 



(2) Post-Maplewood diastrophism — Sauquoit syncline, Alton anti- 

 cline. 



(3) Post-Wolcott diastrophism — Lakeport syncline, Eochester parma. 



(4) Pre-Rochester submergence; source of sediment shifted to west. 



(5) Pre-Lockport erosional unconformity, terminating the Eontaric. 



JVes& 



y^eSi^/e zone in sh 



Figure 4. — Diagram of thin hasal Divisions of the '^Clinton," from Rochester eastward 



to Verona only 



The vertical exaggeration is excessive. Solid vertical lines are the test-wells terminat- 

 ing in these strata and are numbered as in figure 3. Oneida conglomerate largely in- 

 ferred from outcrops to north ; it may extend farther Avest. The diagram suggests that 

 Bear Creek sedimentation was both preceded and followed by faint diastrophic move- 

 ments, and that these movements were initiated still earlier at the close of Medina red- 

 bed deposition. Iron ore in solid black. The horizontal datum is the top of the Reynales 

 limestone. 



Intersj)ersed between these are minor diastrophisms and those weaker 

 pauses in deposition, such as Professor Barrell is calling "diastems," of 

 which the various iron-ore beds furnish special illustrations. The most 

 significant of these minor breaks seem to be those at (a) the top of the 

 red Medina, (h) the Furnacevine iron ore, (c) the Ivirkland iron ore, 

 and (d) the base of the Gates limestone.^^ 



18 This name is defined at the beginning of the following chapter on classification. 



