Transcriber’s Note
Cover and Table of Contents created by Transcriberand placed in the Public Domain.
325
| On The Typical Laurentian Area of Canada | 325 |
| Melilite-Nepheline-Basalt and Nepheline-Basanite from Southern Texas | 340 |
| Some Dynamic Phenomena Shown by the Baraboo Quartzite Ranges of Central Wisconsin | 347 |
| The Chemical Relation of Iron and Manganese In Sedimentary Rocks | 356 |
| Some Rivers of Connecticut | 371 |
| Geological History of the Laurentian Basin | 394 |
| Editorials | 408 |
| Reviews | 410 |
| Analytical Abstracts of Current Literature | 419 |
| Acknowledgments | 423 |
The name Laurentian was given by Logan in 1854 to thegreat series of rocks forming the Laurentides or LaurentianMountains, a district of mountainous country rising to the northof the River and Gulf of St. Lawrence, and extending in anunbroken stretch along the shore of the latter from Quebec toLabrador, a distance of nine hundred miles. This district, withits continuation to the west as far as Lake Huron, being situatedin the Province of Quebec and the adjacent portion of the Provinceof Ontario, and forming part of the main Protaxis of thecontinent, is the “Original Laurentian Area” of Logan. TheLaurentian rocks are now known to extend far beyond the limitsof this area to the west and north, constituting, as they do, byfar the greater part of the Protaxis, and underlying (with subordinatepatches of Huronian) an area of somewhat over two millionsquare miles.1 The area above referred to is, however, the onewhich was first studied and described; it is the “Typical Laurentianarea,” and to it the observations in the present paper will beas far as possible confined.
A general exploration of the area in question, and a moredetailed study of a small part of it—the Grenville District—situatedin the counties of Argenteuil and Terrebonne in the Province326of Quebec, was carried out by Logan and his assistants inthe early years of the Canadian Geological Survey. An excellentrésumé of the results of these studies is given in the“Geology of Canada,” published in 1863, which contains notonly a good description of the general petrog