202 Geological Society : — 
comprised within the Haliburton and Bancroft sheets of the Ontario 
& Quebec series of maps. The paper opens with a short account 
of Logan's work in the original Laurentian area. The main con- 
clusions reached by the author may be thus summarized : — (1) The 
Laurentian System of Sir William Logan consists of a very ancient 
series of sedimentary strata, largely limestones, invaded by great 
volumes of granite in the form of bathyliths ; (2) This sedimentary 
series is one of the most important developments of the pre- 
Cambrian rocks in North America, it presents the greatest body 
of pre-Cambrian limestones on the continent, and it is best desig- 
nated as the Grenville Series; (3) The invading masses of 
granite are of enormous extent : they possess a more or less 
distinct gneissose structure, due to the movements of the magma, 
which developed a fluidal and, in the later stages of intrusion, a 
protoclastic structure in the rock ; (4) The granite-gneiss of the 
bathyliths not only arched up the invaded strata into a series of 
domes, but ' stoped ' out portions of the sides and lower surface 
of the arches, the fragments torn off from walls and roof by the 
invading granite being found scattered throughout the mass of the 
invading rock : this ' stoping/ however, probably developed only a 
small part of the space which the granite now occupies ; (5) The 
invading granite not only exerted a mechanical action upon the 
invaded strata, but also gave rise to a variety of metamorphic 
products, among others amphibolite produced by its action in the 
limestone, which accounts for the fact that whiJe the invaded strata 
are chiefly limestone, the fragments of the latter, where found in 
the granite, consist of amphibolite ; (6) The invading bathyliths 
and allied intrusions of granite occupy the greater part of the great 
Northern Protaxis of Canada, which has an area of approximately 
2,000,000 square miles. It has, therefore, been considered advisable 
to restrict the name Laurentian to this great development 
of the 'Fundamental Gneiss,' which, although intrusive into the 
Grenville Series, nevertheless underlies and supports it; (7) The 
relation of the Grenville Series, which forms the base of the 
sedimentary portion of the geological column in Eastern Canada, to 
the Huronian and Keewatin Series, which are the oldest stratified 
rocks in the western part of the Protaxis, has yet to be determined, 
the two not having so far been found in contact ; nowhere, more- 
over, either east or west, has the original basement on which the 
first sediments were laid down been discovered ; these are every- 
where torn to pieces by the granite-intrusions of the Laurentian. 
November 20th.— Sir Archibald Geikie, K.C.B., D.C.L., Sc.D., 
Sec. B.S., President, in the Chair. 
The following communications were read : — 
1. l Glacial Beds of Cambrian Age in South Australia.' By 
the Bev. Walter Howchin, F.G.S., Lecturer in the University of 
Adelaide. 
The known extension of the beds in question is 460 miles from 
north to south (Onkaparenga Biver to Willouran Bange). The 
