each other by two transverse furrows which are deep. The cusps in the exposed part are of course six in number, but although well developed, and above the tooth in front, they are very slightly worn. The principal wear is in the outer anterior cusp. This tooth, like the last described, is slightly movable in its socket: in magnitude, it is about the same as the sixth tooth, and is greater than the fifth. In construction, it resembles the sixth more than the fifth, having a fourth ridge and a well marked talon. Its cingulum is accessible on the inner and anterior faces, but not on the outer and posterior, the last being in contact with the bone. The crown may be said to be well developed, and evidently has been in use; of course the tooth may be taken out of the category of teeth imbedded in the bone, as the sixth tooth is before it is fairly cut. In another jaw, in which the fifth tooth is fully developed, those in front have disappeared, and the sixth tooth is undeveloped, but displayed by cutting away the bone so as to bring its four ridges into view.

It is obvious from what has been stated, that this tooth is a repetition of the sixth, a superadded tooth, increasing the number from six on a side to seven. It would have been fortunate, if the left side of this jaw had been preserved, but only a fragment of it remains, and this the symphysial part which does not contain any teeth, the four teeth occupying the situation in front having wholly disappeared in both sides of the jaw without leaving a trace of their sockets.

The remainder of this jaw has nothing very remarkable about it. The texture of the bone is moderately sound, and may endure for a succession of ages. The condyloid process has been broken off, and also the coronoid, but the cavity for the implantation of the temporal muscle is preserved, and the angle of the jaw is perfect. The symphysis is entire, of a wedge-like form rather than foliated, and presents no mark of the cavities for the Tetracaulodon sockets; of course it is likely to have been the jaw of a female. The front part of the symphysis measures in a perpendicular direction five and a half inches, and the back part seven inches; the latter is broader than usual, and gives more space for the lingual fossa. The orifices for the issue of the submaxillary and mental vessels are larger, the forefinger being readily admitted into the posterior opening. The canal on the left side is one inch and three eighths in diameter; on the left portion is a trace of an alveolus four inches long.

After a careful examination of the appearance of this jaw in its integral state I thought it best to uncover the extraordinary tooth, and ascertain its situation and extent. This was done not without hesitation, as it might alter the relation of the parts and bring into doubt the existence of an additional tooth. On the inner face of the bone three incisions were made, two vertical

three inches long, and these were united inferiorly by a third horizontal incision six inches long. Then by cutting through the alveolar process, which passed across between the first and second fangs, the large internal plate was removed with some additional projections. When this bone was raised, we found a great molar tooth equal in size to the sixth tooth. The surface of the crown was in superficial extent full as large as that of the sixth; the anterior part rather larger than that of the other. This crown had four ridges, and a talon with a longitudinal furrow through the centre. The ridges had each two cusps, which are unworn except the two anterior; the posterior ridges, not having been fully developed, were not covered with enamel: the talon was of good size and had two or three cusps. Each of the ridges was supported as usual by a pair of fangs, the two anterior separate, the two posterior coalesced into one mass. The anterior fangs passed under the posterior fangs of the sixth tooth. The length of this tooth was seven inches; the width anteriorly four inches; the cingulum measured in circumference sixteen and one half inches; from the point of the fang to the tip of the corresponding second internal cusp seven and one half inches. From the anterior face of the anterior cusp arises an additional projection or cusp. The bone was somewhat shattered in the operation of exposing the tooth, but not sufficiently to disturb that organ, which remains in its original situation, and has never been displaced.

We naturally ask, whether this additional tooth is to be considered a lusus naturæ, or an instance of the power of increased dental development in old age. On page 60 of the work on the Mastodon giganteus, we have said, it is the opinion of some naturalists that the elephant may attain an age which might give him a seventh and even an eighth tooth. Mr. Corse, in his paper on this animal in the Philosophical Transactions of 1779, gives a plate representing a seventh tooth and a cavity behind it, which he thinks might have contained an eighth tooth; but Professor Owen remarks upon it, that if a tooth had existed, there would have been some remains of the calcified plates, and he does not express his belief in the existence of a seventh tooth. No instance of the kind has occurred in the Mastodon giganteus. The M. longirostris has been shown to possess in addition to the six teeth a small vertical premolar above the second and third milk molars in the upper jaw, which gives its even teeth; no such tooth has been discovered in the lower jaw as yet; and none such in the upper or lower jaw of M. giganteus.

No instance of a great supernumerary ultimate molar has been found in any species of Mastodon thus far with the present exception. Anomalies of the teeth both as to number and form are well known to exist. But the laws which govern the dentition of the Elephant and Mastodon are different from those which regulate

dentition in other animals. These two pachyderms having immense teeth develop them, as we have elsewhere said, successively from behind forwards, to prevent the jaws from being overcharged with the weight at any one time. On the whole, we are disposed to consider this as the result of that law, which, in consequence of the hardness of the substances used for food, gives these animals an unusual power of dental development, which may be displayed from circumstances not known to us.

ART. XXXVI.-Supplement to the Mineralogy of J. D. Dana, by the Author.-Number I.

IN continuing in this Journal the semi-annual reviews of mineralogical researches, I propose to give them the form of Supplements to the last edition of my Mineralogy, believing that they will thus prove more convenient to many mineralogical readers of the Journal. The following abstracts cover the first six months since the publication of the work: they are given as briefly as is consistent with their object; and if deemed too concise, they may be taken as an index to the papers where the subjects are discussed at length. My own observations or criticisms are enclosed in brackets.

The new facts which have been brought to light, suggest no essential modification of the general arrangement of the work. Some minor changes in the grouping of the species are proposed, such as the following:-Boltonite according to Dr. J. Lawrence Smith, should be united to Chrysolite: also, as the author shows beyond, from the observations of Haidinger, Partschin should probably be placed near Allanite and Epidote, if not united to one or the other; Mosandrite also should follow Epidote; Keilhauite, should follow Sphene, the probability of this relation, announced by the author, having now become a certainty on crystallographic as well as chemical grounds.

Important contributions to American mineralogy have been recently made by Dr. J. Lawrence Smith, Dr. F. A. Genth, and G. J. Brush. Observations on some American minerals have also been published by Dr. Kenngott of Vienna (including analyses by M. C. von Hauer,) whose "Mineralogical Notices" are generally of great value. But owing apparently to false labels, poor specimens, or other circumstances, many of the results, although intended as corrections, serve only to multiply doubts, at least in Europe if not in this country.

I have adopted an alphabetical arrangement, and distinguished species recently proposed as new, by putting the name in large capitals.

SECOND SERIES, Vol. XIX, No. 57.—May, 1855.

45

1. New Mineralogical Works.

QUENSTEDT: Handbuch der Mineralogie, von Fr. Aug. Quenstedt, Prof. zu Tübingen. 2nd and concluding part. 1854.

KENNGOTT: 60 Krystallformennetze zum Anfertigen von Krystallmodellen, von Dr. Adolf Kenngott, Wien, 1854. Heft 2. A collection of figures to assist in making models of crystals--very convenient and excellent.

SCHEERER: Paramorphismus, und seine Bedeutung in der Chemie, Mineralogie und Geologie, von Dr. Theodor Scheerer, Prof. Köngl. Sächsischen Bergakad. zu Freiberg, 130 pp. 8vo. Braunschweig, 1854.--The work presents a review of Dr. Scheerer's latest results in Isomorphism and Paramorps.

VOLGER: Entwickelungsgeschichte der Mineralien, by G. H. Otto Volger. Zurich, 1854.

2. Notices of Species.*

ACHTARANDITE, Breit.-Achtarandite is a pseudomorph after Helvin according to Breithaupt. Lieb. u. Kopp Jahersb., 1853, 856.

ACICULITE [p. 81].-A mineral, probably aciculite, occurs in North Carolina, at Gold Hill in Rowan Co., according to Dr. F. A. Genth, Am. J. Sci., [2], xix, 16.

ALLANITE [P, 208].-Analyses of Allanite from Orange Co. N. Y., Eckhardt's Furnace, Berks Co., Pa., and Bethlehem, Pa., by F. A. Genth, Am. J. Sci., [2], xix, 20. Specific gravity of the Allanite of East Bradford, Pa., 353, and that of Bethlehem, Pa., 3.935, G. J. Brush.

ALLOPHANE [p. 336]-Analysis of allophane from Polk Co., Tenn., by Dr. C. T. Jackson, Am. J. Sci., [2], xix, 119.

ALSTONITE [p. 451].-Analysis of alstonite, by C. v. Hauer (Jahrb. Geol. Reichs, 1853, 832).

BaC 65.71 ČaĈ 34-29 Si traee = 100.

=

Bac+Čač

ALUM, (Mangano-magnesian), [p. 382].—Analysis by Dr. J. L. Smith of a specimen from the region of the Salt Lake, Utah, Rocky Mts., Amer. J. Sci., [2], xviii, 379. ANAUXITE [p. 505]-Analyses of anauxite from Bilin, Bohemia, by von Hauer (Jahrb. geol. Reichs., 1854, 83, and J. f. pr. Ch., lxiii, 36):

Analysis 1 gives von Hauer the oxygen ratio for the Silica, alumina and water, 8-7232-974: = (nearly) 3:1:1, which is the ratio of the Cimolite of Argentiera and Alexandrowski. Probably a result of the decomposition of augite. ANDALUSITE. [p. 257].-Analyses of Andalusite from Brazil by Damour (Ann. des Mines [5], iv, 53):

Si

Fe

Mn

whence the formula Al Si3. Specific gravity 3.160

ANTIGORITE [p. 281]-Schweizer states (Pogg. Ann., xcii, 495), that the analyses of Antigorite by him should be rejected as not accurate.

APATITE [p. 396].—A locality of apatite in trappean rocks occurs on the Achigan River, 2 miles below St. Roch, Canada, (T. S. Hunt, in Logan's Rep. Geol. Can., 1852-3, 172). The rock consists of glassy feldspar and black hornblende in small grains the apatite is abundantly disseminated in hexagonal prisms, more or less regular.

:

* Kenngott's Mineral Notices, referred to beyond, are published, No. 10, in the Sitzungsber. Akad. der Wissensch., Wien, 1854, xii, 161; No. 11, ib., p. 281 ;No. 12, ib., p. 485; No. 13, (the last No. that has reached us,) ib., p. 701.

APHROSIDERITE, a Chlorite-like mineral [p. 297].-Analysis by v. Hauer (Jahrb. geol. Reichs., 1854, 79, and J. f. pr. Chem., Ixiii, 30):

Fe 32.91 Mg 10:00

10.06 99.32

Si 26:08 Al 20-27 affording the oxygen ratio for the protoxyds, peroxyds, silica and water, 5:4-17:597: 395, or quite nearly 5:4:6:4. Von Hauer appears to prefer the ratio 5:3: 6:4 and deduces the formula Al H4+R5 Si2, and remarks on the nearness of the formula to that of chlorite (Rose), as written by Kenngott.

The aphrosiderite occurs in calcite and specular iron in minute, lustrous, crystalline lamine, of a deep olive-green color. Rather easily decomposed by muriatic

acid.

[Taking the ratio 5:4:6:4 which the analysis gives, the oxygen ratio between all the bases and the silica (excluding the water) is then 9:63:2, the same as in ripidolite (Rose), which would give the ripidolite formula (R3, Al) Si3+Aq in which R3 and Al are here to one another as 4:5; or including these proportions (R3+

1) Si+Aq.

The ratio adopted by von Hauer, 5:3:6:4, gives for the oxygen ratio of the bases and silica 8:64:3, which is the ratio of chlorite (Rose). Thus the liberty taken with the analysis in deducing the ratios is sufficient to transfer the mineral from one of these species to the other.-D.]

ARSENOMELAN and SCLEROCLASE, von Waltershausen.-Description and analysis by W. S. von Waltershausen (Pogg., xciv, 123):-Occurs with the Dufrenoysite in the Binnen Valley in dolomite. Form trimetric: a brachydome of 115° 16'; angle between a plane of the brachydome and that of a macrodome 134° 59′; axes a (vertical axis):b: c = 0·6538:1:10315, [giving for the fundamental vertical prism 91° 47']. Crystals longitudinally striated. Color lead-gray to tin-white, also steel-gray to iron black. Analyses:

S

Pb Fe I. Lead gray; G. 5.393 25910 28.556 44.564 0424 0448 99.922 II. G. 5'405 24.658 25.740 47.586 0.938 = 98-922 G. 5.469 23.949 26.458 49.657 0.629 = 100.693

As

Ag

III. Atomic ratio for the bases, arsenic and sulphur in I, 0:36:061:1-29; in II, 0:38:0555:1-24; in III, 038:056:1-185. As the ratios do not correspond to a simple formula, von Waltershausen regards the compound as consisting of two isomorphous compounds, Pb S+AS S3 (A) and 2Pb S+As S3 (B), and calculates that I, contains A and B in the ratio 3:124:1; II, in the ratio 1:1-234; III, in the ratio 1:0-966. He gives the name Arsenomelan to A, and Scleroclase to B. He observes that A is the formula of zinkenite, except that it contains arsenic in place of antimony, while Scleroclase (B) differs only in its arsenic from heteromorphite or feather ore. The composition of scleroclase is near that obtained by Damour in his analysis of dufrenoysite [see Min., p. 77].

[Zinkenite and Heteromophite are both regarded as trimetric; yet as far as is known, they are far from homoeomorphous for zinkenite has a prism of 120° and occurs in hexagonal compound crystals, while heteromorphite is not in such twins and according to von Waltershausen has nearly the form above given for arsenomelan. The hypothesis that A and B are isomorphous appears therefore to need evidence to sustain it. The angles of arsenomelan are near those of bournonite.-D.] ATACAMITE [p. 138].-Analysis of the atacamite of Copiapo, Chili, by F. Field, (Q. J. Chem. Soc.. vii, 193):

1501

18:00 =

28.35

53.62

18.00

1. Cl 14-94 Cu 56-46 H 17.79 = Cu Cl 28-22 Cu 53.99 H 17.79 2. 56.24 whence the formula Cu Cl + 3CuO+5HO. Specific gravity 4.25. Mallet obtained in an analysis of atacamite (Ramm., 5th Suppl., 57), Ĉu 55.94, Cu 14:54, Cl 16-33, H 12·96, Quartz 0:08 99-85.

AUTOMOLITE [p. 103]-Occurs at Bridgewater, Vermont.

BALTIMORITE [p. 282]. In the Jahrbuch geol. Reichsanstalt, Wien, 1853, No. 1, p. 154, C. von Hauer published an analysis of a specimen from Texas, Pa., labelled Baltimorite, which is copied in the Mineralogy, p. 285, making it to contain 27.15 of silica, 26 of magnesia, &c. In Kenngott's Min. Notizen, No. 11, a very different