198 



INDEX. TO THE STRATIGEAPHY OF NORTH AMERICA. 



Ordovician west of the Frontenac axis. 

 V. Lorraine: Arenaceous shales and mudstones, at times very fine-grained argillites. 

 IV. Utica: Dark-brown and black fossiliferous shales, etc. 

 III. Trenton: Gray impure fossiliferous limestones. 



II. Birdseye and Black River [Pamelia, Lowville, and Black River]: Heavy-bedded impure fossil- 

 iferous limestones and fine-grained compact lithographic beds at the base. 

 I. Rideau [Ste. Marie"]: Mostly red and yellow (at times green) colored sandstones; shallow- 

 water deposit; false bedding prevalent; a basal series resting unconformably upon the subja- 

 cent Archean crystallines [Chazy. — B. W.]. 



The following tables of the geologic formations which make up the Ordovician 

 near Ottawa, Montreal, and Quebec, northwest of the St. Lawrence-Champlain 

 fault, are taken from a paper by Ami. '^* 



[Part of] synoptical table of (he geological formations about Toronto, Ontario. 



System. 



Ordovician. 



Unconformity. - 

 Pre-Cambrian. 



Formation. 



Lorraine. 



Utica- 



Trenton. 



Birdseye and 

 Black River. 



Character of strata, etc. 



Light yellowish green 

 and gray calcareous 

 and magnesian and 

 arenaceous shales or 

 mudstones, some 

 very fine grained ar- 

 gillites, bluish gray in 

 color. 



Dark-brown and black 

 bituminous shales 

 (only reported and 

 observed in drillings 

 from deep wells). 



Dark and light gray and 

 yellowish-gray i m - 

 pure fossiliferous lime- 

 stones with shaly part- 

 ings. 



Dark-gray impure, but 

 also and for the most 

 part fine-grained com- 

 pact yellowish-gray 

 lithographic 1 i m e - 

 stone, with basal beds 

 of a calcareo-arena- 

 ceous or arkose na- 

 ture. 



Characteristic fossils. 



Diplograptus hudsonieus 

 Nicholson, Monotrypella 

 undulata Nich., Zygospira 

 headi Billings, Platystro- 

 phia hiforata Schlotheim, 

 V. lynx Eichwald, Drepa- 

 nodus arcuatus Hinde, Dis- 

 tacodus incurvatus Hinde, 

 Pronodusf politus Hinde, 

 Lyrodesma poststriatum, 

 Liospira subconica Hall, 

 Modiolopsis modiolaris 

 Hall, Byssonyckia radiata 

 IB.., Modiolopsis pholadi- 

 formis H., Orthocecus la- 

 mellosum H., Ormoceras 

 crebriseptum'B.., Triarthrus 

 becki Gieen, Favistellastel- 

 lata H., T. calydna N., 

 Tetradium minus Safford. 



The characteristic fossils of 

 this formation as exposed 

 at Whitby and vicinity 

 east of Toronto are Lepto- 

 graptus flaccidus Hall, Or- 

 thograptus quadrimucrona- 

 tus^., Leptobolus insignis 

 H., Schizocrania filosa H., 

 Zygospiramodesta Sa.yjjy- 

 rodesma pulchellum Em- 

 mons, Trocholites ammo- 

 nius, TriarthriLs canadensis 

 Smith, T. becki Green. 



Diplotrypa sp., Dicranopora 

 sp., Plectambonites sericea 

 Sowerby, Orthis (Dalman- 



■ ella) testudinaria Dalman, 

 Rhynchotrema sp. 



Jsochilina lithographica n. s . . 



Thickness. 



Between 600 and 650 

 feet. Varies in thick- 

 ness in different ex- 

 posures. Thickness 

 depends upon amount 

 of denudation and ero- 

 sion. 



About 100 feet. 



About 550 feet in bore 

 holes. 



About 160 feet in bore 

 holes. 



" According to a personal communication from Dr. Ami, the sandstones at Rideau are of Potsdam age. They 

 are not of widespread occurrence in this district. Sandstones which are similar but are of Chazy age locally form the 

 base of the Ordovician succession (Storrington, near Kingston, and island off Pallideau) and were described by Logan 

 (Geology of Canada, 1863, p. 196) as the Ste. Marie sandstone. Hence in Dr. Ami's judgment Rideau in this section 

 must give place to Ste. Marie. — B. W. 



