OF PRE-CAMBRIAN ROCKS 215 
respectively as the “‘ Anorthosite”’ or ‘‘ Norian” series, the “‘ Grenville” 
series, and the “Fundamental” or “Ottawa Gneiss.”? Logan’s 
classification may thus be represented as follows: 
Anorthosite or Norian Series 
Upper Portion ae ea) Grenville series 
Lower Portion . . . Fundamental or Ottawa Gneiss 
Upper Laurentian 
Lower Laurentian | 
The subsequent investigations by Adams in the district to the 
east of that studied by Logan showed that the Anorthosite (or Logan’s 
Upper Laurentian series) really consisted of great intrusions, and 
that the associated limestones, etc., assigned by Logan to the ‘‘ Upper 
Laurentian” were really part of the Grenville series. There therefore 
exist in these pre-Cambrian areas of the province of Quebec two 
divisions, namely, the Grenville series and the underlying Funda- 
mental Gneiss. The relations of these have not been worked out in 
such detail as in the case of the Ontario area, but it is believed that 
here also the Fundamental Gneiss comes against the Grenville 
series with an intrusive contact. 
VI. RECOMMENDATIONS OF THE COMMITTEE CONCERNING 
CORRELATION AND NOMENCLATURE 
The committee considers that over the whole area covered by 
their investigations—namely, the Adirondack Mountains, that portion 
of eastern Ontario which they examined, the “ original Laurentian 
area” in the province of Quebec and its continuation to the east as 
far as the river St. Maurice—the pre-Cambrian sedimentary develop- 
ment is represented by one great series. This series is essentially 
identical in petrographical character throughout the whole region. 
The only locality where the possible (Coleman would say probable) 
existence of a second uncomformable sedimentary series was suggested 
by the facts observed, was that on the Queensboro road, east of 
Madoc, Ontario. It is, however, still a matter of uncertainty as to 
whether the conglomerate here developed marks the base of an over- 
lying, infolded, uncomformable series or not. 
In Logan’s original classification of the Laurentian this term— 
apart from the Upper Laurentian which was proved to be composed 
essentially of anorthosite intrusions—included two series differing 
in character, namely, the Lower Orthoclase (Fundamental) Gneiss 
