A greenish substance, nearly or quite isotropic, which is associated with calcite in places, and commonly forms pseudomorphs after hornblende, is regarded as chlorite. In association with calcite it occasionally shows aggregate polarization and sometimes has a more serpentine-like appearance, where it probably consists in part of that mineral. The iron ore is in black angular grains, which have a metallic lustre and are all thought to be primary. Its general characters are those of magnetite, some of the larger grains containing cores of leucoxene, thus indicating its titaniferous nature. Needles of apatite penetrate both feldspar and hornblende. The rock thus belongs to the dark-colored trap dykes, or lamprophyres, and agrees most closely with the characters of Camptonite, of which it is a fairly typical specimen. The known occurrences of Camptonite in eastern North America include Montreal and the shores of Lake Memphremagog in Canada, as well as several localities in the states of New Hampshire and Vermont, southern Maine and eastern New York. The nearest of these, that at Lake Memphremagog, is about fifty miles south of the present occurrence. Camptonite is commonly, though not invariably, an accompaniment of highly alkaline rocks, such as nepheline syenites, no occurrence of which is known, however, nearer than Brome and Yamaska mountains, some fifty miles to the westward. From the presence of such dykes 1 "The Trap Dykes of the Lake Champlain Region," by J. F. Kemp and V. F. Marsters. Bull. U.S.G.S., No. 107. "Camptonites and other Intrusives at Lake Amer. Geologist, July, 1895. Memphremagog," by V. F. Marsters. 2"Geology of the Castle Mountain Mining District." Weed and Pirsson. Bulletin U.S Geol. Survey, No. 139, p. 111. The authors here cite Brogger's opinion, deduced from the study of the basic rocks of Gran, Norway (Q. J. G. Soc. London, Feb., 1894), that Camptonite is not necessarily indicative of the presence of a definite type of granular plutonic rock as formerly supposed." along the shores of Lake Champlain Prof. Kemp has pointed out the probable occurrence of an area of nepheline syenite in that region, which has not yet, however, been discovered, though amongst the many igneous rocks. of these localities even a series of such a character may yet be found perhaps running along the western border of the Appalachian folding. The other rocks of igneous origin in this vicinity arethe well-known serpentines of the Eastern Townships, three miles to the south, which contain irruptive masses of hornblende granite, and are bordered on the south by a volcanic agglomerate, the matrix of which is an altered porphyrite. Both the first and second of these have been fully described by Dr. F. D. Adams. Of the former, Dr. Adams says, "the alteration to serpentine was found to be complete, with the exception of a few irregular-shaped remnants which occur in one of them. They are probably bastite or some allied mineral derived from the alteration of a rhombic pyroxene, which was a constituent of the rock from which the serpentine was derived." The hornblende granite is described as "composed essentially of quartz, orthoclase, plagioclase and hornblende, with a little titanic iron ore. The hornblende, as is usual in granites, seldom has a good crystalline form. It is light green in color, strongly pleochroic, shows in many places the characteristic cleavage and often occurs twinned. It sometimes contains little pleochroic 'hofe surrounding minute doubly refracting crystals. Its angle of extinction, as is often the case with the hornblende in granites, is large. The greatest angle measured was 24, and this was in a section in the zone of the orthopinacoid and clinopinacoid, nearly but not quite coinciding with the latter plane. Many of these hornblende grains assume a fibrous form at their edge, but this is especially the case at the extremi 1 "Notes on the Microscopic Structure of some Rocks of the Quebec Group," by F. D. Adams. Rep. Geol. Surv. Can., 1880-1-2, part A. ties of the elongated patches in which it often occurs. The rock is no longer fresh. The feldspar, of which a very considerable portion is plagioclase, is a good deal decomposed, and the hornblende is altered in a very peculiar and hitherto unobserved manner. It is a very frequent associate of the serpentines throughout the Eastern Townships, and is commonly believed by miners to be a necessary condition of the occurrence of the better class of asbestos deposits. It is enclosed in the serpentine, and from this fact, as well as its finer crystallization near the contact, is presumably intrusive through it, although the actual contact is generally concealed. The porphyrite consists of a fine feldspathic base, containing phenocrysts of plagioclase and a few large individuals of epidote and chlorite, possibly representing primary hornblende. It, too, is considerably decomposed, and it contains veins and secondary aggregates of quartz, chlorite and epidote. No quartz, that is certainly primary, could be distinguished. The relations of this rock are not so easily determined as the last, yet are tolerably certain. It appears to have reached about the same degree of decomposition as the granite, but has suffered less dynamic metamorphism, and although the difference in the susceptibility of various rocks to metamorphic agencies prevents this fact from furnishing a safe clue to their relative ages, yet it cannot be entirely overlooked. The porphyrite also contains fragments of Cambrian slate which probably elsewhere overlies the serpentine, but this fact, again, is not yet clearly established. But a block, apparently of the same agglomerate which is found in Lot 13, Range XIII. of the township of Cleveland, nearly two miles north of the serpentine belt, contains fragments which are macroscopically indistinguishable from the hornblende granite just described. This evidence, which appears conclusive, is substantiated by the fact that the course of local glaciation has here been such as to convey a large number of serpentine boulders, whose character is unmistakable, for a distance of three or four miles north of the occurrence of that rock. Accordingly the porphyrite may be regarded as the latest intrusion along the serpentine belt. At a distance of a mile and a half north of the locality of the lamprophyre dyke described above, there is an interbedded sheet of amygdaloidal trap rock, probably diabase. This is also highly altered in character, and, like the other rocks that have been mentioned, is apparently much older than the dyke. Whether it has any genetic connection either with the dyke or the igneous rocks to the south of it, it is impossible at present to say. The following order of age can, however, be ascertained for the other rocks of igneous origin: 1. The parent rock of the serpentine. 2. Hornblende granite, intrusive through the serpentine. 3. Porphyrite, which was intruded generally along the southern contact of the serpentine with the sedimentary slates, and with the fragments thus included forms an agglomerate. 4. The Camptonite dyke, which is much later in age, and, being a common associate of rocks of a different character, is only doubtfully connected with the others in origin. 1 Dr. R. W. Ells. Ann. Rept. Geol. Survey of Canada, 1894, p. 86 J. 2 Ottara Naturalist, Jan., 1901. WAS MOUNT ROYAL AN ACTIVE VOLCANO ? By J. S. BUCHAN, K.C. Mount Royal is commonly described as the root or remnant of an old volcano, which has been worn down through long ages by the action of the elements, and its peak shorn by ice fields carried over it during the great subsidence of the Glacial Period, until it was reduced to its present comparatively small proportions. Doubtless many have pictured in their own minds the Mountain in all its glory, in the far distant time when the struggling forces burst through the barriers which restrained them, and seem to see again a great mountain peak piercing the sky, with volumes of smoke and clouds. of ashes thrown out and scattered over the surrounding country, while rivers of lava ran down its almost perpendicular sides. It may even be supposed that some have contemplated this picture with a sigh of regret, when they think what a magnificent advertisement the Volcano would be for Montreal, provided, of course, it was removed to a safe distance from the City. Be that as it may, the question as to what was the height and magnitude of Mount Royal when it had reached its greatest proportions, and the conditions which then prevailed, possesses an intense interest, which the difficulties in the way of its solution only tend to increase. At the outset, it must be admitted that the records containing the story of the Mountain have for the most part been swept away, and any conclusions based on those which remain are largely conjectural. It will, however, also be admitted that any attempt, however humble, to bring together the facts which bear on the subject, and to state such conclusions as may appear to flow from them, may |