60 



Thickness 

 feet 



(3) Massive crystalline limestone which projects beyond the face of 

 the cliff and forms a persistent horizon-marker. Numerous examples of 

 Homotrypa streetsvillensis are found V/ 2 



(2) Alternating limestone and shale, characterized by exceedingly 

 numerous examples of Homotrypa streetsvillensis. The large fauna is com- 

 posed of Homotrypa streetsvillensis, Byssonychia radiata, Hebertella occi- 

 dentalism Zygospira modesta, Modiolopsis sp., Stigmatella incrustans, 

 Platystrophia clarkesvillensis, Heterotrypa cf. robusta, Orihodesma cf. 

 canaliculatum, Byssonychia robusta, Opisthoptera fissicosta, Homotrypa 

 communis, Homotrypa cf. richmondensis, Hallopora subnodosa, Hetero- 

 trypa cf . rugosa A^/i 



Zone of Ischyrodonta miseneri: 



(1) Massive limestone beds which become argillaceous toward the 

 bottom, crowded with well-preserved specimens of Ischyrodonta miseneri, 

 Byssonychia robusta, and Opisthoptera fissicosta. Other species occurring 

 in the interval are: Platystrophia clarkesvillensis, Hebertella occidentalis 

 (abundant), Modiolopsis concentrica, Byssonychia grandis, Pterinea 

 demissa, Bellerophon cf. mohri, Ortonella cf. hainesi, Orthodesma cf. canalicu- 

 latum, Lophospira bowdeni. This horizon extends to water-level 2 



In examining the rocks of this last interval, thin sections were accidentally 

 cut of numerous small round objects, measuring about one-quarter of a milli- 

 metre in diameter, with hollow centres and with radiating structures in their 

 walls. They were at first thought to be organic in origin, but the opinion of 

 Dr. Ulrich, to whom they were referred, is that they are oolites. 



SECTION No. 14.— EAST SIDE OF RIVER, SOUTH OF BRIDGE OPPOSITE FLOUR 

 MILL, OPPOSITE MIDDLE OF STREETSVILLE VILLAGE (480 to 493'/ 2 ) 



Meadowvale Member 

 Columnaria Reef: Thickness 



feet 

 (6) Limestone with Columnaria alveolata, Columnaria calicina, 

 Tetradium approximatum, Stromatocerium huronense, Hebertella occidentalis, 

 Platystrophia clarkesvillensis, etc 2 



Streetsville Member 

 Zone of Bythopora meeki: 



(5) Alternating layers of shale and thin limestone. The weathered 

 limestone contains numerous examples of Bythopora meeki. The following 

 fossils also occur: Columnaria alveolata, Stromatocerium huronense, 

 Hebertella occidentalis, Platystrophia clarkesvillensis, Atactoporella densa, 

 Homotrypella dubia, Homotrypella hospitalis, Heterotrypa simplex, Hetero- 

 trypa simplex maculosa, Hallopora onealli creditensis, Batostoma cf. varians, 

 Byssonychia grandis 2 



Stromatocerium Reef: 



(4) Clay with Stromatocerium huronense large and abundant, also 

 Columnaria alveolata, Columnaria calicina, and Tetradium approximatum . 3 



Zone of Homotrypa streetsvillensis: 



(3) Thin alternating bands of shale and limestone. The fauna 

 consists of the following species: Columnaria alveolata, Hebertella occi- 

 dentalis, Platystrophia clarkesvillensis, Zygospira modesta, Ceramoporella 

 ohioensis, Homotrypella hospitalis, Homotrypa streetsvillensis, Monticulipora 

 parasitica multipora, Mesotrypa patella, Heterotrypa robusta, Hallopora 

 onealli creditensis, Hallopora aequalis, Stigmatella incrustans, Byssonychia 



sp., Lophospira bowdeni 3'/2 



(2) Projecting, massive limestone layer with: Homotrypa streets- 

 villensis, Homotrypa creditensis, Amplexopora solitaria, Orthoceras sp., 

 Lophospira bowdeni, Lophospira tropidophora IV2 



(1) Alternating beds of shale and limestone extending to water-level. 

 The limestone is literally one mass of the zoaria of Homotrypa streets- 

 villensis. The following fossils also occur: Hebertella occidentalis, 

 Platystrophia clarkesvillensis, Heterotrypa cf. rugosa, Eridotrypa cf. simula- 

 trix, Stigmatella incrustans, Byssonychia robusta 3'/2 



