MIDDLE AND UPPER ORDOVICIAN. 



[Pari of] syiwptical table of geological formations about Ottawa, Canada. 



199 



System- 



Silurian. 



Ordovician. 



Formation. 



Medina. 



Lorraine. 



Utica. 



Trenton. 



Character of strata, etc. 



Bright brick-red argilla- 

 ceous and arenaceous 

 shales or marls, occa- 

 sionally spotted or 

 mottled green. 



Buff-weathering fine- 

 grained brittle shales 

 and mudstones, at 

 times arenaceous. 



Dark-brown and black 

 bituminous soft shales 

 and limestone bands 

 interstratified in the 

 baaal portion of this 

 formation. 



Nodular and evenly 

 bedded, for the most 

 part bluish-gray, light- 

 weathering impure 

 limestones and shales, 

 fossiliferous, marine 

 sediments, in part 

 bituminous, cherty. 



Characteristic fossils. 



No fossil organic remains 

 have as yet been detected 

 in these shales. 



ZygospiraheadiBillings, Bys- 

 sonychia radiata Hall, 

 Modiolopsis modiolaris 

 Conrad, M. pholadiformis 

 Hall, Liospira subconica 

 Hall, Calymene senaria 

 Conrad, Cyrtolites omatus 

 Con. 



Lepiograptus fiacddus Hall, 

 Orthograpttis quadrimucro- 

 natus Hall, Schizambon 

 canadensis Ami, Schizocra- 

 nia filosa Hall, Batosto- 

 mella erratica TJlrich, Tur- 

 rilepas canadensis Henry 

 Woodward, Stephanella 

 sancta Hinde, Triarthrus 

 spinosus Billings, Asaphus 

 latimarginatus Hall {=A. 

 canadensis Chapman) En- 

 doceras tenuistriatum. Hall. 



LicrophycuS ottawaensis Bil- 

 lings, Pasceolus globosus 

 B., Astylospongia parvula 

 Billings, Streptelasma cor- 

 niculum Hall, Archxocri- 

 nusmicrobasalis Bill., Clei- 

 ocrinus magnificus B . , 

 Glyptocnnus ramulosus B . , 

 Heterocrinus canadensis B . , 

 locrinus subcrassus M. and 

 W.fReteocrinusstellarisTi., 

 Amygdalocystites florealis 

 Bill., Ateleocystites huxleyi 

 B., Comarocystites puncta- 

 tus B., Pleurocystites fili- 

 textus B . , Agelacrinites 

 dicksoni B . , Monticulipora 

 billingsi Foord, Batostoma 

 ottawaensis Foord, Praso- 

 pora selwyni Nicholson, 

 Solenopora compacta B., 

 Orbieuloidea circeB., Shen- 

 idiwn merope B., Rafines- 

 quina altemata Conrad 

 (Emmons), Tremutis otta- 

 waensis B., Ambonychia 

 amygdalina B . , Pterinea 

 trentonensis Conrad, Conu- 

 laria trentonensis H., Pro- 

 towarthia cancellata Hall, 

 Eccyliomphalus trentonen- 

 sis Con., Ophileta otta- 

 waensis B . , Trochonema 

 umbilicalum H., Hormo- 

 toma bellicincta H., Ortho- 

 ceras python B., 0. otta- 

 waense B., Serpulites dis- 

 solutus B., Zygospira re- 

 curvirostra H., Isotelus gi- 

 gas De Kay, Bronteus lu- 

 natus B., Harpes ottawaen- 

 sis B. 



Thickness. 



About 100 feet in thick- 

 ness. On one of the 

 outliers examined a 

 60-foot well was sunk 

 in these shales. 



Exact thickness not as- 

 certained, but prob- 

 ably not less than 100 

 or 150 feet. 



From 60 to 75 feet. 



From 450 to 500 feet. 



