1864.] GRANT ON THE GEOLOGY OF THE OTTAWA. 421 



constituting the south side of a synclinal form, on the north side 

 of which it rises in Hull, from beneath the higher members of the 

 Lower Silurian series. In Hull it is observed about five miles 

 north of the Ottawa, and about two miles east of the Gatineau, 

 where it is also brought into view by a dislocation which branches 

 in Osgoode and Gloucester, from the one previously mentioned, 

 and, passing in a direction somewhat west of north, crosses the 

 Ottawa at the Little Chaudiere Falls, and shows a downward throw 

 on the east side. According to Professor Dana, during the first 

 half of the Lower Silurian era, the whole east and west were alike 

 in being covered with the sea, and that in the first or Potsdam 

 period, this continent was just beneath or at the surface. After- 

 wards, in the Trenton period, the depth became greater, and 

 afi'orded pure waters for the very abundant marine life. 



Calciferous Sand-Rock succeeds Potsdam sandstone, and 

 the characteristic portion of this formation, in Canada, is a granu- 

 lar magnesian limestone or dolomite, of a dark bluish-gray color, 

 crystalline, strongly coherent, weathering yellowish brown, and 

 frequently containing small geodes, filled either with calcareous 

 spar, quartz crystals, sulphate of barytes, sulphate of ^strontia, or 

 sulphate of lime. Its fossils are very imperfect, and in most 

 cases only moulds of these are to be found. In some places the 

 upper part of this formation is of a bluish-gray calcareous argilite. 

 "When exposed to the air, it turns yellow or brown, and frequently 

 develops a bituminous odor. The calcareous beds in many districts 

 yield a poor description of lime, and hence the term bastard 

 limestones is applied to them by settlers and others. Calciferous 

 Sandrock forms part of the great series of strata called the Quebec 

 Group. It is seen along the south shore of the Ottawa in many 

 localities from Carillon to the Chats. At Aylmer it occurs on 

 both sides of the river, and from the Alumette Island extends 

 south to Prescott, at which point it crosses the St. Lawrence into 

 the United States. A little below Prescott, on the spot where the 

 battle of the Windmill was fought, gentle undulations are to be 

 observed in the strata of this formation, but more particularly on 

 descending the river from Haitian d to this point. According to 

 Sir W. Loii-an, the total thickness of this formation is about 300 

 feet. 



Chazy Limestone overlies the Calciferous formation, and 

 derives its name from Chazy, in the State of New York, west of 



Vol. I. CO No. 6. 



