SURVEY. JUST PUBLISHED, THE REPORT OF PROGRESS FROM THE COMMENCEMENT TO 1863. Illustrated by 498 wood-cuts. One volume large octavo, pp. 1011. Price $5. From the London Saturday Review. "The style in which the work has been got up, the precision of the drawing and the accuracy of the wood-cuts may almost challenge comparison with the execution of similar productions on this side of the Atlantic. There has been a steady persistence in the conduct of this remarkable survey, honorable alike to the successive Governments that have encouraged it, and to the officers who have carried out the work. No other Colonial Survey has ever yet assumed the same truly national character; and the day may come-if ever the "Imperial Colony" shall claim and obtain independence-when the Scientific public of a great nation, looking back upon the earlier dawnings of science in their land, shall regard the name of Logan, a native born, with the same affectionate interest with which English geologists now regard the names of our great geological map-makers, William Smith and De la Beche." DAWSON BROS., MONTREAL. THE AIR-BREATHERS OF THE COAL PERIOD; A descriptive account of the remains of Land Animals found in the Coal Formation of Nova Scotia, with remarks on their bearing, on Theories of the Formation of Coal and of the Origin of Species, by J. W. DAWSON, LL.D., F.R.S., F.G.S., Principal of McGill University, Montreal, 8vo. pp. 81; illustrated by 7 full page Lithographs containing over 200 drawings. A few copies have been containing 11 illustrations. PRICE $1.00. published with a Microscopic Photograph PRICE $1.50. Montreal: DAWSON BROTHERS;-Toronto: CHEWETT & Co.;-New York: BAILLIERE BROTHERS;-London: H. BAILLIERE. This Magazine is published bi-monthly, and is conducted by a Com- EDITORS FOR THE YEAR 1863-4. J. W. DAWSON, LL.D., F.R.S., Principal of McGill College. PROF. S. P. ROBBINS. REV. A. F. KEMP. General Editor.-DAVID A. P. WATT. EX OFFICIO. The Corresponding and Recording Secretaries of the Natural History Contributions to Lithology; By T. Sterry Hunt, M.A., F.R.S.; of the Geological Survey of Canada.............. 161 THE CANADIAN NATURALIST. SECOND SERIES. CONTRIBUTIONS TO LITHOLOGY.* BY T. STERRY HUNT, M.A., F.R.S.; of the Geol. Survey of Canada. III. ON SOME ERUPTIVE ROCKS.† In Silliman's Journal for March 1860 (2nd, xxix, 282) there is a short note, pointing out the existence, in the vicinity of Montreal, of several interesting classes of eruptive rocks, including quartziferous porphyries, trachytes, phonolite, dolerites, and diorites. It is proposed in the third part of the present paper to describe the results of some chemical and mineralogical examinations of these rocks, and to give by way of preface a description of their geogra phical distribution and geological relations. They may be considered geographically as belonging to two groups; of which the first and more important for the number and variety of its rocks may be conveniently described as the Montreal group. It consists of a succession of intrusive masses along a belt running nearly transverse to the undulations of the Notre Dame Mountains, which are the prolongation of the Appalachians into eastern Canada. Commencing at Shefford Mountain, an isolated trachytic mass not far removed from the western base of the Notre Dame range, we find, going westward, the detached hills known as Yamaska, Rougemont, Rouville or Beloeil, Montarville or Boucherville, Mount Royal or Montreal, and Rigaud Mountains; the last being distant about ninety miles from Shefford. Brome Mountain, which • Concluded from page 36. + From Silliman's Journal, vol. xxxviii. VOL. I. L No. 3. occupies a large area to the south of Shefford, approaches within two miles of it. In like manner, a few miles to the south of Beloeil is another intrusive mass known as Mount Johnson or Monnoir; making in all nine hills of eruptive rock belonging to the Montreal group. Besides these, numerous smaller intrusive masses in the form of dykes are met with around and between the hills. From Mount Royal to Rigaud Mountain, a distance of about thirty miles, a gentle undulation of the strata is observed, which increases to the westward of Rigaud, and finally gives place to a considerable fault.. This disturbance has been traced to the Laurentide hills on the Lac des Chats, 140 miles west of Montreal; but to the eastward the strata exhibit no evidence of this transverse undulation, unless the appearance of the intrusive rocks already mentioned be supposed to indicate the prolongation of a fracture without sensible dislocation. The whole of these eruptive rocks rise through unaltered paleozoic strata, which however, in the immediate vicinity of the intrusive rocks, exhibit a local metamorphism. The hills of Shefford, Brome, and Yamaska break through the strata of the Quebec group, and lie a little to the east of the great line of dislocation which, in this region, brings up the lower members of the paleozoic series against the superior portion of the Lower Silurian, and divides into two districts the great paleozoic basin. (Geology of Canada, pp. 234, 597.) The other hills all belong to the western division of this basin, and break through various members of the Lower Silurian series from the Potsdam to the Hudson River formation. Among the numerous dykes which traverse not only the sedimentary strata but the intrusive masses, there are some which intersect the conglomerates of St. Helen's Island. These are of uncertain age, but repose unconformably on the Lower Silurian series, and enclose pebbles and masses of Upper Silurian limestone characterized by fossils of the Lower Helderberg period. (Ibid., p. 356.) This group of intrusive rocks offers very great varieties in composition; thus Shefford and Brome consist of what we shall describe as a granitoid trachyte, while the succeeding mountain, Yamaska, and the most western, Rigaud, both consist in part of a kind of trachyte, and in part of diorite. Monnoir and Beloeil also consist of diorites, which however differ from the last two, and from each other; while Rougemont, Montarville, and Mount Royal consist in great part of dolerites, presenting however many varieties in composition, and sometimes passing into pyroxenite. The dole |