32 



Furthermore, throughout nearly the whole distance 

 these strata dip in a southerly direction at high angles. 



It must be noted, also, that along the whole length 

 of this section a continuous alternation of beds of varying 

 character is presented, and therefore it is not a foliation, 

 but a true bedding that is observed. It is, furthermore, 

 to be noted that, although this series may have been re- 

 peated by isoclinal folding, there is no stratigraphical 

 evidence that such is the case, and this folding has nowhere 

 brought up the basement upon which the series was 

 deposited — a fact which indicates again that the series, 

 even if so folded, is extremely thick. 



It may be safely stated that the Grenville series 

 presents by far the thickest development of Pre-Cambrian 

 limestone in North America, and that it presents at the 

 same time one of the thickest series of Pre-Cambrian 

 sediments on that continent. 



Not only has the Grenville series a great thickness, 

 but it has a great superficial extent. It is exposed more 

 or less continuously over an area of 83,000 square miles 

 (208,000 sq. km.) in Eastern Canada and the State of New 

 York. In areal extent, therefore, it can be compared in 

 North America only with certain of the greatest develop- 

 ments of the Palaeozoic limestones, as, for instance, the 

 Knox dolomites of the southern Appalachians. In all 

 probability, its original areal distribution was considerably 

 greater than above stated, although this cannot be 

 definitely determined on account of the great erosion to 

 which the Laurentian protaxis has been subjected. 



It may here be mentioned that the 'Hastings series,' 

 a designation given by Logan to certain rocks of the 

 Madoc district, has proved, as Logan conjectured might 

 be the case, to have no independent existence, but to be 

 merely the less metamorphosed portion of the Grenville 

 series seen in the southern part of the Bancroft area. It 

 is, however, practically certain that in this Madoc district 

 the comparatively unaltered rocks, which were designated 

 by Logan as the Hastings series, really consist of two 

 unconformable series; and it is possible also that in the 

 Grenville series, as shown upon the Bancroft sheet, there 

 may be two formations separated by an unconformity, 

 as suggested by the occurrence of certain conglomerates. 

 If, however, there are proved to be two formations within 

 this area, these are identical in petrographical character, 



