326 



MINERALS AND GEOLOGY 



bufo (fig. 174) is also a common Corniferous type. In the district 

 under review, the formation occupies two large areas, separated by a 

 broad intervening belt of the succeeding Hamilton or Lambton for- 

 mation. The more eastern of these areas extends over portions of 

 Welland, Haldimand, Norfolk, Brant, Oxford, Perth, Huron and 

 Bruce ; and the western area occupies parts of Lambton, Kent and 

 Essex. Exposures occur more particularly on or near the shore of 

 Lake Erie in the following townships : Bertie, Humberstone (as at 

 Rama's farm, near Port Colborne, a noted fossil locality), Dunn, 

 Rainham, Walpole and Woodhouse. Also in North and South 

 Cayuga; near Woodstock village ; and at St. Mary's (another locality 

 especially rich in fossils). The formation outcrops likewise at various 

 places in Carrick, Brant, Bruce and Kincardine ; and again, farther 

 south, as near Port Albert and Goderich, and in the vicinity of 

 Amherstburg in Maiden. At many of these localities, and especially 

 at the large exposure in Maiden, building-stones of very superior 

 quality are obtained. 



The Hamilton or Lambton Formation,* as defined in Canada, 

 represents merely the middle portion of the " Hamilton formation " 

 of the New York geologists. It consists mainly of soft calcareous 

 shales associated with some beds of encrinal limestone. The fossils 

 are identical for the greater part with those of the Corniferous forma- 

 tion ; but the brachiopods, Spirifer mucronatns (fig. 185) ; Spirigera 

 concentrica (fig. 187); Atrypa reticularis (fig. 188); and Ortkis 

 Vanuxemi (fig. 199) are especially abundant in these higher beds. 

 The formation in this district is estimated at about 250 feet in thick- 

 ness. It extends across the counties of Norfolk, Elgin, Kent, 

 Middlesex and Lambton, and also the south pait of Huron, but is 

 much obscured throughout this area by overlying clays, sands, and 

 other Drift and superficial deposits. The best exposures occur in the 

 township of Bosanquet, in the north-west corner of Lambton. The 

 formation is chiefly of interest as constituting the essential petroleum 



* The name by which this formation is commonly known, is derived from the village of 

 Hamilton, in Madison county, New York. It is often supposed, in Canada, to refer to our city 

 of Hamilton, on the western extremity of Lake Ontario, where the strata belong to a much 

 lower horizon that of the Medina formation, lying at the base of the Upper Silurian series. 

 In consequence of this very prevalent misconception (of which some curious instances might 

 be given), the writer proposed some years ago to call this group of strata, as occurring in 

 Canada, the Lambton formation, after the county in which it is principally developed in 

 Western Ontario. 



