While welcoming discussions of theory, The Journal will be devoted mainly to a study of the more practical questions of railway transportation, finance, banking, money, agriculture and kindred subjects in Economics and Statistics. Contributions from writers of all shades of economic belief are welcomed. While contributions ought to be essentially scientific, they need not necessarily be technical or uninteresting to the general reader Articles may be expected at an early day from Max Wirth, DR. VON KANNER, MR. SEGER, GEO. S. COE, A. N. KIAER, and others. Among those who will also contribute are FRANCIS A. WALKER, GUSTAV COHN, SIMON NEWCOMB, CARL MENGER, LUIGI COSSA, ADOLPH C. MILLER, HENRY C. ADAMS, EDWARD W. Bemis, E. VON BÖHM-BAWERK, STEPHEN BAUER, and many others. Subscription, in the United States, Three Dollars per Annum; to Foreign Subscribers, Thirteen Shillings. THE JOURNAL OF POLITICAL ECONOMY, CHICAGO. ILL. EXTENSION WORLD Is a Monthly Fournal devoted to the extension and popularizing of higher education. It is under the official direction of the University Extension Department of the University of Chicago. The design of its contents A. News. will be seen in the following scheme. I. A broad and general view of University Extension and kindred systems, noting developments of especial interest all over the world. 2. Periodical letters from the chief Universities and societies engaged in Extension work at New York, Philadelphia, Oxford, Cambridge, etc. 3. News of interest from all institutions which have organized Extension work. 4. News of special import from District Associations, Local Centres, etc. B. Leading Articles and (Editorials) dealing with I. The Extension movement generally; kindred or allied movements; Chautauquas, Y. M. C. Associations, Public Libraries and higher education generally. 2. The educational features and organism of University Extension; Class-work, Exercises, Lecture-study, Correspondence, Training of Lecturers, Local efforts and Organization, Student Associations. 3. Articles dealing with matter of general literary and scientific interest. D. Lists and Notices of Summer Meetings, THE UNIVERSITY EXTENSION WORLD will be a monthly journal, each number consisting of 16 to 24 pages (82X111⁄2 inches), and cover. Subscription price, $1.00 per year. Special rates to clubs and agents. Address, THE UNIVERSITY EXTENSION WORLD CHICAGO, ILL. THE JOURNAL OF GEOLOGY MAY-JUNE, 1893. ON THE TYPICAL LAURENTIAN AREA OF CANADA. THE name Laurentian was given by Logan in 1854 to the great series of rocks forming the Laurentides or Laurentian Mountains, a district of mountainous country rising to the north of the River and Gulf of St. Lawrence, and extending in an unbroken stretch along the shore of the latter from Quebec to Labrador, a distance of nine hundred miles. This district, with its continuation to the west as far as Lake Huron, being situated in the Province of Quebec and the adjacent portion of the Province of Ontario, and forming part of the main Protaxis of the continent, is the "Original Laurentian Area" of Logan. The Laurentian rocks are now known to extend far beyond the limits of this area to the west and north, constituting, as they do, by far the greater part of the Protaxis, and underlying (with subordinate patches of Huronian) an area of somewhat over two million square miles. The area above referred to is, however, the one which was first studied and described; it is the "Typical Laurentian area," and to it the observations in the present paper will be as far as possible confined. A general exploration of the area in question, and a more detailed study of a small part of it-the Grenville Districtsituated in the counties of Argenteuil and Terrebonne in the Prov Accepting the distribution of the Laurentian in the far north, given by Dr. G. M Dawson, as correct, the area is 2,001,250 square miles. This does not include the outlying and separated areas occurring in Newfoundland, New York State and Michigan. Vol. I.-No. 4. 325 ince of Quebec, was carried out by Logan and his assistants in the early years of the Canadian Geological Survey. An excellent résumé of the results of these studies is given in the "Geology of Canada," published in 1863, which contains not only a good description of the general petrographical character and arrangement of the rocks which make up the area, but is accompanied by an atlas containing two maps illustrating this description, one showing the general distribution of the Laurentian in the eastern part of the Dominion, and the other its stratigraphical relations in the smaller area above referred to. As a result of these studies, Logan announced his belief that the Laurentian System consisted of two great unconformable series of sedimentary rocks, to which he gave the names Upper and Lower Laurentian. The latter he considered to be divisible into a lower and an upper portion, which sub-divisions he regarded as probably conformable to one another. In the course of time these several series came to be known as the Anorthosite or Norian Series, the Grenville Series and the Fundamental or Ottawa Gneiss. Logan's views may then be represented as follows: Subsequently, in the southeastern corner of the Province of Ontario, in the district lying to the north of the eastern end of Lake Ontario, another series of rocks was discovered-the socalled Hastings Series. Logan supposed this to come in above the Grenville Series, while Vennor, who subsequently examined the district, believed it to be equivalent to the lower part of the Grenville Series already mentioned. The When these investigations were carried out, the microscope had not as yet been seriously employed in petrographical work. precise composition of many of the rocks making up the several series was not recognized, the effects produced by great dynamic action were not duly considered, and the foliation possessed in a high degree by some and to a certain extent by almost all these rocks was considered, in all cases, to be a more or less obliterated survival of original bedding. The detailed mapping in the field, accompanied by microscopical work in the laboratory, by which alone conclusive results can be obtained in working out the structure of complicated areas of crystalline schists, was not carried out, in fact in many districts the construction of detailed maps was at that time practically impossible. It is not surprising therefore that, although excellent in the main, some of the results arrived at have since proved to be erroneous. It is proposed, in the present paper, to place before the readers of this JOURNAL in as brief a manner as possible, a general account of the several series of rocks occurring in this area, and to point out what, in the opinion of the present writer, seems to have been satisfactorily established concerning the statigraphical position and mutual relations of these ancient rocks and what still remains to be determined by further study, and in conclusion to give a short sketch of the evolution of this portion of the continent. 66 The Fundamental Gneiss.- Exposed over very wide stretches. of country in Canada, and making up in all probability by far the larger part of the Archean Protaxis, is the Fundamental Gneiss," sometimes called, from its great development about the upper waters of the Ottawa River, the "Ottawa Gneiss." It is composed essentially of orthoclase gneiss, usually reddish or greyish in color. Of this there are a number of varieties, differing from one another in size of grain, relative proportion of constituent minerals and in the distinctness of the foliation or banding. It is sometimes rich in quartz, while at other times this mineral is present in but very small amount. It is usually poor in mica and bisilicates. Dark bands of amphibolite are not uncommon, while basic hornblende or pyroxene gneisses occur in some places. Other schistose rocks are rarely found. great areas it is often nearly uniform in character and possesses a foliation which can only be recognized when exposures of considerable size are examined. On this account it is often referred to as a granitoid gneiss, a designation, however, which by no Over |