170 A. < . LAWSON — RELATK >NS OF THE A In II IAN OF CAN \ l>\. 



various gneiss, Bchist, limestone, quartzite, :in<l conglomerate formations, 

 which, not being easily separable from the foliated granite rocks, have been 

 sometimes classed with the latter as Laurentian. 



The Uppee Division. 



lenclature. — The upper division is of very varied lithological character, 

 and various oames have been applied to it, or to portions of it, in different 

 regions. Until recently it has been customary to apply the term Huronian 

 tn a part of this upper division on account of its supposed equivalence to the 



ies of locks so named by Logan and Hunt in L855.* But if the original 

 conceptions of these eminent geologists and t he more recent contentions of 

 Irving, corroborated by Professors X. EL Winchell and A.. Winchell, are 

 <onvct — viz., that the Huronian and Animikie are geologically equivalent, — 

 then we cannot in reason perpetuate the incongruity of applying the same 

 name to two groups of rocks which lie one ou either side of probably the 



atesl hiatus in American geological history. The term Huronian must 

 be retained for the -roup of rock- on Lake Huron first SO named and its 

 equivalents; ami. in view of the evidence which has been adduced of the 

 unconformable superposition of that group upon the Archean and it- prob- 

 able equivalence with the Animikie, which rests upon the Archean in glaring 

 unconformity, it seems inappropriate at present to apply the term Huronian 

 to any portion of the Archean. We are thus, at the outset of any inquiry 

 into the Archean, hampered by the lack of an acceptable designation for 

 the great system of rock- which constitutes ii> upper division. Even if the 

 Huronian group be demonstrated to lie upon the remote side of the great 

 post-Archean hiatus, it would then be only one of several groups thai go to 

 form the system which constitutes the upper division of the Archean com- 

 plex, ami the system itself would .-till he nameless. Ai least one other great 



up of locks — the < ' lutchiching i possibly the equivalent of the Montalban 

 of Hitchcock I — baa been brought to light, which is not second in taxonomic 

 importance to the various belts of rock- Bimilar to the Keewatin, which have 

 been correlated with the Huronian. 80, granting that the Huronian shall 



one day hold an unchallenged position in Archean taxonomy, il will not 

 have a higher rank than that of a group."] 



1 'i am the Geological Mad and the ( olleciion "i 

 lomic M ■ . nihil Ion at P E, Logan a ■ rry 



Ibition ol in 1 lo- sketch, in which the 



term Hu iwn an the Anl iken 



■ Huron, and the whole is the " Huronian or 



1 unconformably upon I he I iaui 



to them by the 

 I'm v, in tin' tcheme published in I i Annual !•'•■■ 



■1 1 in \ re I lean com pie \. The 

 herwlse 1 « ith any n" 1 "'! i 



