Geological Survey of Canada. 35 



The fossiliferous rocks, iu a large part of Canada, maintaining 

 an attitude approaching horizontally, give a much more even sur- 

 face than the corrogated series coming from beneath them, and 

 this, combined with a generally good soil, renders them more fa- 

 vourable for agricultural purposes. It is over them, too, that the 

 River St. Lawrence maintains its course, affording an unrivalled 

 means of exit for the produce of the land, and of entrance for the 

 materials that are to be received in exchange. It is only a natu- 

 ral result of these conditions that the area supported by the fos- 

 siliferous rocks should be the first settled. This area, however, 

 constitutes only between 60,000 and 80,000 square miles, while 

 the whole superfices of Canada comprehends 330,000 square miles. 

 or about five times the amount. 



Four-fifths of Canada thus stand upon the lower un fossiliferous 

 rocks, and it becomes a question of some importance, before it has 

 been extensively tested by agricultural experiments, to know what 

 support this large area may offer to an agricultural population. 

 An undulating surface, derived from the contorted condition of 

 the strata, on which it rests, will more or less prevail over the 

 whole of this region ; but the quality of its soil will depend on the 

 character of the 'rocks from which it is derived. 



These rocks, as a whole,* have very generally been called 

 granite, by those travellers who with little more than casual ob- 

 servation have described them, without reference to geological 

 considerations. The rains of granite are known to constitute an 

 indifferent soil from their deficiency in lime, and hence an unfa- 

 vourable impression is produced in respect to the agricultural 

 capabilities of any extended area, when it is called granitic. 

 Such soils are however never wanting in those essential elements 

 the alkalies, which are abundant in the feldspars of the granite. 



In the reports of the survey, the Laurentian rocks have been 

 described in general terms as gneiss, interstratified with impor- 

 tant masses of crystalline limestone. The term gneiss, strictly 

 defined, signifies a granite with its elements, quartz, feldspar and 

 mica, arranged in parallel planes, and containing a larger amount 

 of mica than ordinary granite possesses, giving to the rock a 

 schistose or lamellar structure. When hornblende instead of 

 mica is associated with quartz and feldspar, the rock is termed 

 syenite, but as there is no distinct specific single name for a rock 

 containing these elements in a lamellar arrangement, it receives 

 the appellation of syenitic gneiss. 



