The principle I have exemplified above may not be novel; but as I have never met with it, chemists, as well as manufacturers (especially of colors), will probably also find it of interest, and certainly highly practicable and easy of execution.

36 Beekman street, New York, Feb. 3d, 1860.

3. New Chemical Journal.-The Chemical News (with which is incorporated the Chemical Gazette), edited by WILLIAM CROOKES. London: Weekly. Price 3d., stamped 4d. 8vo. 12 p. each number. This new Journal commenced on the 10th of December last, and eight numbers have already reached us. The contents are divided under Scientific and Aualytical Chemistry, Technical Chemistry, Pharmacy, Toxicology, &c., Proceedings of Societies, Notices of Patents, Correspondence, Scientific Notes and Queries, Laboratory Memoranda, Miscellanies, and Answers to Correspondents. Mr. Crookes is favorably known by several valuable researches, and thus far has shown good judgment and spirit as an editor. His verbatim reports of the late lectures of Dr. Faraday (the Holiday lectures) at the Royal Institution, attest his appreciation of the true sources of vitality for such a journal.

4. American Druggists' Circular and Chemical Gazette; N. Y. Feb. 1860. 4to.-Although chiefly special and wholly technical in its objects, this Journal (which has now reached its 4th volume, whole number 38) is conducted by Mr. Mayer and others, in a manner to entitle it to rank as a valuable coadjutor in technical chemistry.

II. GEOLOGY.

1. On some of the Igneous Rocks of Canada; by T. STERRY HUNT, F.R.S. (In a letter to one of the editors, dated Jan. 1860.)-There occurs in the district of Montreal a series of isolated hills running nearly east and west for a distance of ninety miles along the line of an undulation which has disturbed the lower Silurian strata. These hills, which often cover considerable areas, consist of igneous rocks which have apparently been solidified under a considerable pressure, and have subsequently been exposed by the denuding action which has removed from around them the soft and unaltered paleozoic strata. The names of these mountains counting from the west are Rigaud, Mount Royal, Montarville, Beleil, Rougemont, Yamaska, Shefford and Brome, to which we may add Monnoir a similar mass lying somewhat to the south of Beloeil.

I am now engaged in the study of the various rocks composing these mountains, which offer great diversities in lithological character and composition. Prominent among them we may mention the trachytes, which in their various types of compact, granular, porphyritic and granitoid are abundant. The mountains of Brome and Shefford appear to be made up entirely of a granitoid trachyte, which consists of crystalline orthoclase, without quartz, and with small portions of hornblende or mica, sphene and magnetite. The orthoclase in a great number of these rocks which I have analyzed contains like sanidin a large proportion of soda. The other varieties of trachyte which occur in veins and dykes often contain a portion of carbonates amounting to from 6.0 to 180 p. c. and consisting chiefly of carbonate of lime with some magnesia and

iron. Some of these rocks pass into phonolites through the admixture of a silicate which gelatinizes with acids and has the composition of natrolite. This mineral in one case amounted to more than 400 p. c. of the rock, the remainder being orthoclase with a small amount of carbonates.

A large part of the mountain of Yamaska consists of a coarsely crystalline diorite the feldspar of which approaches anorthite in composition, while an apparently similar diorite, which makes up the mass of Monnoir, contains oligoclase in large crystals. Other diorites from this series contain labradorite; mica and sphene, in small quantities, are often present.

Dolerites are also abundant, and sometimes pass, owing to a scarcity of feldspar, into an augite rock, generally with ilmenite and magnetite. A fine-grained dolerite from Rougemont contains abundance of crystallized olivine, and a large part of Montarvilles consists of a remarkable granitoid rock, made up of a crystalline feldspar, in some parts at least labradorite, with sparsely disseminated crystals of black angite, a little brown mica, and a great abundance of crystals of honey-yellow olivine, which amount to more than 450 p. c. of the mass. The composition of this olivine I have found to be silica 37-17, magnesia 39-68, protoxyd of iron 22:54 99.39.

Many of these diorites and dolerites, except in their lithological structure, closely resemble the stratified rocks made up of anorthie feldspar, with hornblende and pyroxene, and containing magnetite and ilmenite, which are so abundant in the Laurentian system, suggesting the notion that the intrusive masses may be nothing more than these stratified rocks displaced and injected among the Paleozoic strata. Durocher has already pointed out a similar resemblance between the intrusive rocks of some parts of Scandinavia, and the subjacent gneiss.-(Bul. Soc. Geol. France, [2] vi, 33.)

The granitoid trachytes as well as the dolerites, diorites and peridotite (olivenite rock), make up mountain masses, while the earthy and porphyritic trachytes and the phonolites are generally found cutting the above, and the adjacent strata. The absence of quartz or of any excess of silica from all these rocks is a remarkable feature. Farther to the east, however, intrusive granites are very abundant; these penetrate the Devonian strata but are older than the carboniferous. Quartziferous plutonic rocks are also abundant in the county of Grenville, where they penetrate the Laurentian series. These plutonic rocks consist of dolerites, syenites and eurites, which are in their turn cut by dykes of very beautiful porphyries. The base of these is jasper-like, black, red or green in color, and encloses crystals of red orthoclase and occasional grains of quartz. The analysis of the base shows it to consist of the elements of orthoclase with an excess of silica and a little oxyd of iron. The syenites are cut by large veins of chert, and in the vicinity of these have been changed into a sort of kaolin from a decomposition of the feldspar, which may have been the source of the silicious accumulations. This group of igneous rocks, which is overlaid by the Potsdam sandstone is very unlike those which we find penetrating the paleozoic

strata.

The details of my investigations on these rocks, so far as completed, will be found in the Report of the Geological survey of Canada, for the last year, now in press; a first portion has already appeared in the Report for 1853-56, p. 485. It is by the systematic study of different series of igneous rocks that we may hope to arrive at just notions as to their origin, their mode of formation and their relations to metamorphic sedimentary rocks.

2. Notes on the Dolomites of the Paris Basin, etc.; by T. STERRY HUNT, F.R.S. (In a letter to one of the Editors, dated Montreal, Feb. 3, 1860.) The gypsums of the Paris basin are evidently not of epigenic origin but regularly stratified and alternating with marls and limestones. In September, 1855, I visited with Elie de Beaumont and several members of the Geological Society of France, the gypsum quarries at the hill of Chaumont, and there insisted upon the views which I have since urged in this Journal (vol. xxviii, p. 365) upon the different origins of gypsum. For a report of my remarks on that occasion see the Bulletin de la Société Geologique de France, [2], xii, 1306.

I have subsequently shown in the memoir just cited in the last volume of this Journal that the formation of these stratified gypsums by the double decomposition of bicarbonate of lime and sulphate of magnesia involves the production of carbonate of magnesia, which unless carried away or decomposed by an irruption of sea water will be found to overlie the gypsums forming the dolomite which is their common associate. The presence of carbonate of magnesia in the gypsiferous series of the Paris basin has hitherto been unnoticed, and having at the time above mentioned collected specimens from the quarries at Chaumont I was recently induced to examine the so-called white marls which overlie the gypsiferous series, and find them to be magnesian. The analyses of two specimens, one penetrated by seams of gypsum, gave each about 600 per cent of dolomite mingled with clay. The Paris gypsums then offer no exception to the general rule.

Beneath the gypsiferous series and in the lacustrine group known as the lower travertine, or St. Owen limestone, occur beds of a whitish, very fissile, shaly matter, enclosing concretions of menilite (opal), and consisting of a hydrated silicate of magnesia, identical with meerschaum or quincite in composition, intermingled with small portions of earthy carbonates. I have examined a specimen of this mineral which I collected near Paris and find it to be the same with that described by Dufrénoy and Berthier as occurring in similar positions in various other localities. This appearance of beds of a silicate of magnesia approaching tale in composition, in the midst of unaltered deposits, is interesting inasmuch as it seems to show that such silicates may be formed in basins at the earth's surface by the reactions between magnesian solutions and dissolved silica. I have many years since described the existence of similar silicates among the deposits during the artificial evaporations of natural alkaline waters, and farther inquiries in this direction may show us to what extent certain rocks consisting of calcareous and magnesian silicates may be directly formed in the moist way.

I propose to send you very soon a supplement to my paper on Gypsums and Magnesian rocks, describing some recent experiments which

confirm what I have already announced that no dolomite is formed in the experiment of Von Morlot and Haidinger, recently resuscitated by Charles Deville, and appealed to by Prof. Phillips in his last Annual Address to the Geological Society of London, as resolving the problem of the origin of dolomite. This double salt is however readily formed when a mixture of the moist amorphous carbonates (such as is obtained by precipitating in the cold by an excess of carbonate of soda a solution of the chlorids of calcium and magnesium in equivalent proportions), is gradually heated under pressure.

3. New Palæozic Fossils; by J. H. McCHESNEY. Chicago, 1859. 8vo. pp. 64. In this publication the following species from the Carboniferous rocks of the Western States are noticed as newly described:

CRINOIDEA.-Platycrinus ornogranulus, P. inornatus, Scaphiocrinus longidactylus, Zeacrinus bifurcatus, Z. mucrospinus, Actinoerinus asterius, A. tenuisculptus, A. subæqualis, A. Fosteri, A. subventricosus, A. urnæformis, A. Hurdianus, A. æquibrachiatus, A. Andrewsianus, A. Hageri, Forbesiocrinus Pratteni.

BRACHIOPODA.-Orthis, Kaskaskiensis, O. Lasallensis, O. Pratteni, 0. Richmonda, Productus asperus, P. symmetricus, P. Wilberanus, P. tubulospinus, P. fasciculatus, P. inflatus, P. pileiformis, Ambocelia gemmula, Spirifer transversa, S. subelliptica, S. perplexea, S. subventricosa, Retzia subglobosa, Athyris spiriferoides, A. orbicularis, A. differentius, Terebratula inornata, Rhynchonella Eatoniæformis, R. explanata, R. carbonaria, R. Algeri, Trematospira Mathewsoni, Discina caputiformia. LAMELLIBRANCHIATA.-Leda Oweni, L. gibbosa, L. polita, Nucula parva, N. cylindricus, N. rectangula, Astartella varica, Edmondia concentrica, Allorisma clavata, A. sinuata, Myalina Swallovi, Nuculites Vaseyana, Pinna Adamsi, Syringopora multattenuata, Cyathoxona prolifera. GASTEROPODA.-Bellerophon ellipticus, B. vittatus, B. Blanyana, B. Stevensiana, Pleurotomuria Beckwithana, P. nodomarginata, Natica Shumardi, Platyceras crytolites, Platyostoma Peoriensis, Bucania Chicagoensis. CEPHALOPODA.-Nautilus Forbesianus, N. Illinoiensis, N. quadrangulus, N. nodocarinatus, Gonitites Hathawana, Cyrtoceras (Lituites?) giganteum, Trochoceras Desplaniensis, Orthoceras Rushensis, O. Knoxensis.

The typography of this brochure is very good, and the descriptions of the species show that the author has a wide acquaintance with the Carboniferous fauna of the West. We think, however, that the science would present to the student a much less formidable array of difficulties, if Paleontologists would on all occasions give accurate measurements of the species they describe. Throughout this book, for instance, the size of the individual is recognized as a specific character, and yet as no dimensions are given it must be impossible for even the most experienced practical naturalist to decide whether O. Lasallensis, O. Richmonda and O. Pratteni are small or large forms; whether two lines or two inches wide. The first mentioned of these species is also said to have the "surface marked by sharp rugose radiating striæ increased by implantation," but so have a great many other Orthides, and until some standard for comparison is furnished, all the students of this book, except those who may have access to the original specimens, must remain in doubt upon the question as to whether there are ten or twenty striæ in the width

of one line. We find it stated further that in O. Richmonda the striæ are "finer and less rugose" than they are in O. Lasallensis while in O. Pratteni they "are not so distant and not so rough," as in either of the other two, but as we have no means of ascertaining their size in the first named species, which is here made the standard, all that relates to the surface characters of the second and third might have been left out without detracting anything from the value of the description. No doubt all this appeared to be sufficiently clear to the author while he was engaged with the specimens before him, but we think upon a little reflection he will agree with us, that without some clue to the size and surface characters of these species, they cannot be identified. Where a shell is said to be smaller or larger than some other species which has been described in some other book, the difficulty would be somewhat less, provided that access could be had to that book, and even then, such questions as "how much smaller?" or "how much larger?" cannot be decided. By adding two or three lines to their descriptions, paleontologists may add a vast deal to the value of their labors, and save others engaged in the same pursuits much perplexing, and too often fruitless, intellectual toil. It is not always possible to give figures of new species, but it is easy to furnish measurements. The absence of these is the great defect in the work before us, and it is a defect that may be observed in books of much greater pretensions. We notice a new genus, (AMBOCELIA) among the Brachiopoda, which is said to have been "recently established by Prof. James Hall," in the "Regents' Report of the State of New York for the present year," (meaning 1859). Has this report been published? If not, then the genus is not established. No author can establish a genus before he has published his description, and, even then, he may not succeed in shewing that it is new.

The practice of antedating genera and species should be discountenanced, as it cannot be beneficial to science. Where specific names are derived from names of persons or places, the initial should be a capital letter, a rule which has been of late much disregarded.

4. Explorations in Nebraska.-Dr. F. V. HAYDEN, in a letter to Prof. DANA, dated Deer Creek, Nebraska, Dec. 1, 1859, states, after speaking of the interest of the region, that as soon as the grass is sufficiently high this coming Spring, and the swollen streams permit the passage of pack trains (which cannot be sooner than the first of June), Capt. Reynolds proposes to divide his party into two divisions-one party in charge of Lieutenant Maynadier, Asst., will pass up the Wind River Valley along the western side of the Big Horn Mountains. The other division under Capt. Reynolds will proceed up the Platte to the South Pass, exploring the Wind River Mountains-the two parties to spend the 4th of July at Clark's Pass. Here Lt. M.'s party will proceed down the Yellowstone to Fort Union, and Capt. R.'s party will reach the same point by crossing at the head waters of the Missouri and descending that stream, and thence to the States as soon as possible. Such is the programme of explorations; it may be slightly varied, but in any case will traverse a country very interesting for geology.

Dr. Hayden, in addition to his geological labors, has since 1852 interested himself in ethnographical studies, and will have by the end of this trip material enough for a large volume on this subject.