4 ROY A L SOCI KT V OK CA N A DA 



witli new interpretations of structure, it is often extremely difficult to 

 restrain the tendency to make the changes in nomenclature keep pace 

 with the changes in one's opinions, as regards structure and relations of 

 the various rock masses. 



The nomenclature of Canadian Geology dates back for nearly eighty 

 years. Prior to that time but little was known as to the rock formations 

 in this country from the scientific standpoint. Brief notes had appeared 

 in some of the journals of early explorers belonging to the Hudson's Bay 

 Company in the far north, but otherwise the geological structure of this 

 country was practically unknown. An entirely fresh field for research 

 was presented, a field abounding in the grandest and most complicated 

 investigation. 



Comprehensively speaking, the subject of Canadian Nomenclature 

 may be considered in the order of time under three heads. Of these the 

 first relates to the earlier years of scientific investigation, and may be held 

 to include the period between the year 1820 and the establishment of the 

 Geological Survey of Canada, in 1842. In this the nomenclature is 

 essentially the same as that employed by the British Survey, since the 

 explorers of that early date received their scientific training in the 

 British school. 



The second period may be said to begin with the appointment of Sir 

 W. E. Logan as director of the Geological Survey, which was organized 

 by the joint governments of Ontario and Quebec in the year last men- 

 tioned. While some of the original terms, adopted from the British 

 Survey, were still retained by Logan to distinguish the broad groups or 

 systems, it was found more convenient to adopt the scale of formations 

 which was at that time in use by the Geological Survey of the State of 

 New York, where, at a comparatively early date, the nomenclature had 

 been well developed, especially as regards the Palaeozoic formations. 



The third period, which may be said to have its rise in the introduc- 

 tion of the purely Canadian terms Laurentian and Huronian, early in 

 the second half of the century, has, through the detailed examination of 

 the geological structure of the Dominion, resulted in establishing a 

 nomenclature largely Canadian in character. Many of the terms thus 

 introduced have, however, a purely local significance, while others have 

 been applied to large groups of strata. On the broad lines however, the 

 names tidoptcd for systems, which were established by the British Survey, 

 from the Cambrian upward, are still mnintained; while in tiie case of 

 the Palaeozoic formations, the terms originally employed in the New 

 York Survey are continued in use as best meeting the requirements of 

 the science in Canada. 



The earliest information relating to the Geology of Canada is ap- 

 parently found in the journals of Sir John Franklin and Sir John Kich- 



