10 New York State Museum 



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Figure 27 Lower and Middle Cambrian fossils 245 



Figure 28 Lower Ozarkian fossils 246 



Figure 29 Canadian outcrops 264 



Figure 30 A East-west section across Lake Champlain in the 

 vicinity of Plattsburg. B East-west section 

 across the Hudson river at Albany, from the Scho- 

 harie valley (Gilboa) to the Hoosick valley (North 



Petersburg) 265 



Figure 31 Lower Canadian rocks. Schaghticoke shales, 



Schaghticoke, Rensselaer county 269 



Figure 32 Ordovician and Cambro-Ordovician outcrops 273 



Figure 33 Lower (Chazyan) and Middle Ordovician outcrops. . 274 



Figure 34 Upper Ordovician and Lower Silurian outcrops 275 



Figure 35 Lower Ordovician rocks. Cliff of Chazy limestone, 



Valcour island, Lake Champlain 277 



Figure 36 Lower Ordovician rocks. Normanskill graptolite 



shales, Kenwood, Albany county 280 



Figure 37 Middle Ordovician rocks. Trenton limestone, Tren- 

 ton Falls, Utica, Oneida county 284 



Figure 38 Canadian and Ordovician fossils: graptolites, gastro- 

 pods, cephalopods 294 



Figure 39 Ordovician fossils: corals, bryozoan, brachiopods. . . . 296 

 Figure 40 Ordovician fossils: cystoids, crinoid, pelecypods, 



gastropods and cephalopods 297 



Figure 41 Ordovician fossils: trilobites 299 



Figure 42 Silurian outcrops 312 



Figure 43 Middle and Upper Silurian outcrops 314 



Figure 44 A Section from Mount Pisgah in the Catskills 

 (Schoharie county) north to Benson (Hamilton 

 county). B Section through western New York 



along the 78th meridian 316 



Figure 45 Lower and Middle Silurian rocks. Medina beds, 

 Clinton and Lockport groups, Niagara gorge below 



the bridge, Niagara county 322 



Figure 46 Lower and Middle Silurian rocks. Medina and 



Clinton beds 329 



Figure 47 Silurian fossils: worm trail, graptolites, corals, cys- 



toid, crinoids, bryozoans 348 



Figure 48 Silurian fossils: brachiopods, pelecypods, gastropods. 350 

 Figure 49 Silurian fossils : pteropod, cephalopods, trilobites, 



eurypterid, ostracod 351 



Figure 50 Devonian outcrops: Lower, Middle and Upper 367 



Figure 51 Upper Silurian — Lower Devonian rocks. Manlius 

 and Coeymans limestone, at Haile's Cavern, 

 Indian Ladder region, the Helderbergs, Albany 

 county 372 



