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has its lower division two-lobed, the lower lobe looking like a second anal fin. The specimen, which he thought full-grown, was about one foot and a half long. The teeth in front differ much from those on the sides and back of the mouth; they are quite small in front, gradually becoming larger, and then again smaller ; the anterior teeth are trilobed ; the lobes gradually diminish backwards, become flat, and then rounded on their upper surface; there is a ridge on the median line, the remains of the three cusps. In the New Holland species, the front teeth have the median cusp much the longest, the back teeth being much the broadest.

Professor Agassiz compared these teeth with the fossil teeth he had received from Indiana. The teeth of the genus Psammodus resemble the back teeth of Cestracion, and are marked by numerous minute points ; those of the genus Strophodus resemble Cestracion, having also a central prominence; in the genus Ozodus, the teeth are undulated, like the second form in Cestracion, but with lines radiating from each of the three cusps; in the genus Helodus (perhaps to be suppressed) the teeth have a prominent tubercle, like the anterior teeth of Psammodus; another reason for suppressing the former genus is that it is always found with the latter; in the genus Petalodus the teeth are much compressed and spreading, with a narrow root.

These are the same genera as are found in Europe ; the specific identity he had not as yet determined. Other European sharks having no living representatives are also found here. The genus Ctenoptychius, the whole margin of whose teeth is serrated; the genus Hybodus, with cylindrical teeth, longitudinally striated, like those of Saurians, from the folds of the enamel ; the genus Dendrocladus, having large dorsal spines, sometimes two feet long, which are always found with the teeth. Speaking of the gigantic species which must have borne these spines, he remarked that it was neither the first nor the last created members of any class in the animal kingdom which were the giants of that class; but rather those created at the middle epochs.

Professor Peirce made a communication, illustrated by diagrams, on the "collision of solid bodies.” He believed that the speculations hitherto brought forward were radically defective, and comparatively useless; the collision of atoms only had hitherto been considered, instead of combinations of atoms.

Three hundred and ninetieth meeting. December 13, 1853. – SEMI-MONTHLY MEETING. The PRESIDENT in the chair.

The Corresponding Secretary announced a valuable bequest of books on the Infusoria, from the late Thomas Cole, Esq., of Salem, a Fellow of the Academy, consisting of Ehrenberg's great work, Kütsing's Phycologia, Müller's Animalcula Infusoria, Johnston's Zoöphytes, and Recherches Chimiques et Microscopiques sur les Conferves, Bisses, Tremelles, etc., avec 36 Planches, par Girod-Chantrans (4to, Paris, 1802).

On motion of President Walker, the following resolutions were unanimously adopted :

Voted, That the American Academy feel very sensibly the kind remembrance of their lamented associate, Mr. Cole, in the valuable legacy now received, and would express their sincere thanks to Mrs. Cole for the delicate generosity with which she has invested the expressed intentions of her lamented husband with the authority of a bequest.

Voted, That the Librarian be directed to affix to the volumes now presented a statement that they are a bequest from their late associate, Mr. Thomas Cole."

Professor Lovering made a verbal report on the letter of Mr. C. O'Brian, requesting an abstract of the Academy's proceedings, which had been referred to the Publishing Committee. He did not see any objection to furnishing such an abstract, thereby expressing the willingness of the Academy to grant the request, without implying any sanction or recommendation of the journal he was about to establish. It was

Voted, That the Secretary be allowed to furnish to Mr. O'Brian such portions of the records of the Academy as he may think proper."

Dr. J. Wyman exhibited the lower jaw of a mastodon from South America, brought from Chili by Lieutenant Gilliss. This animal ranged the whole of the continent, from 50 north latitude to 40° south. It has been found at great elevations in 34° south, at the height of 1,400 feet above the level of the sea; in Quito, Humboldt found it at the height of 7,200 feet; Mr. Darwin says it has appeared on the limits of perpetual snow. In these cases the land has been elevated since the deposition of the remains.

The number of species found here is doubtful; Cuvier made three, M. augustidens, M. Humboldtii, and M. Andium, of the last two one being small and the other large. De Blainville maintained that there was only a single species. It is not reasonable that M. augustidens should be found here ; from the figures given by Falconer and others, Dr. Wyman thinks there are two species; all the teeth found are referable to two sizes, one about six inches and a half long, the other from nine to ten inches. The jaw he exhibited confirmed the view that there are two species, one of which is of small size ; it was of small size, yet was that of an adult animal, as shown by the sixth molar. He had also another tooth differing so much from the others that perhaps a third species might be made out. It would not be strange if two species were found here, as in India, according to Falconer, eight or ten species are found in a limited district.

Dr. C. T. Jackson exhibited a branch of the Mistletoe, with the flowers, obtained from an oak-tree of North Carolina.

Dr. C. T. Jackson gave some account of the copper and gold mines of North Carolina ; some of the copper mines are old gold mines which were worked till they became unprofitable from the presence of water; now, improved machinery permits them to be worked with profit. The principal copper ores are the yellow and gray sulphurets.

He described in some detail the coal region on Deep River, North Carolina ; the coal is very bituminous, containing little sulphur, and is excellent for the manufacture of gas. He thinks there is a true coal basin; the strata dip down at an angle of 20°, then become horizontal, and, as he believes, rise again at about the same angle. He is inclined to think this a portion of the Lias or Oolitic group. Many scales of ganoid fishes, fish and Saurian coprolites, and minute fossil shells, resembling Cypris, are found in great abundance. The plants are not numerous, except in the grindstone grit under the coal; they resemble the plants of the Lias of Europe. Some bones, said to be Saurian, and perhaps Chelonian, have been found.

Professor W. B. Rogers remarked, that the age of the Deep River coal is probably the same as that of Eastern Virginia. The lithological characters are the same; the fossil plants, shells, and fish found are the same in the two regions. The topographical relations of the two regions are also the same. He does not believe that there is a coal basin at Deep River, but merely layers one over the other, all dipping at the same angle, running down and thinning out against the rocks below: he doubts if any great amount of coal exists there. On a recent visit to the new red sandstone of Virginia, he found the same fossils as in the coal measures, and the same in the new red sandstone of Pennsylvania. He concludes that all these formations are very nearly of the same age, more recent than is generally supposed, and that they belong to the Lias formation.

Dr. Jackson was not certain of the existence of a true coal basin there, though he thought there was as much evidence of it as is generally found ; he had not, however, observed the dip at the other extremity of the basin corresponding in angle with that at Deep River.

Professor Agassiz remarked, that the age of this deposit was very interesting to him; the fishes did not agree either with those of the Trias of Southern Germany or the Lias of England, but seemed intermediate between the two; he was inclined to think that the new red sandstone of this country belonged to a group intermediate between the Trias and Lias, of which there was no representative in Europe.

Professor H. D. Rogers observed that this would indicate a more recent age for the bird-tracks of the Connecticut Sandstone.

Professor Agassiz remarked, in reference to the footmarks of the Potsdam Sandstone, which Professor Owen had described as those of turtles, but which he at the same time maintained were those of Crustaceans, have now been admitted by Owen himself to belong to the latter; so that there is no evidence that reptiles have been found below the coal.

Professor H. D. Rogers alluded to bones of reptiles having been found in Germany in strata equivalent to the carboniferous limestone, one degree older than the coal. Professor Agassiz doubts if these are reptilian bones.

Dr. Hayes connected the coal deposits of the two States by the additional fact, that the chemical constitution of the accompanying rocks, according to his own examination, is the same.

Professor Agassiz presented a list of fishes found in the Tennessee River, in all thirty-three species, and of several genera not found in Europe. He mentioned the fact, that many exclusively American species, found in the Southern States from Virginia downwards, are not found in the more Northern States; he indicated several localities of small extent, which have fishes exclusively their own, so that any former communication of rivers could not explain their limited geographical distribution. The genera are common over extended localities, but each region has its representative species.

Three hundred and ninety-first meeting. December 27, 1853. — Semi-Monthly MEETING. The Academy met at their Hall, the Corresponding Secretary, and afterwards the PRESIDENT, in the chair.

The Recording Secretary being absent, Mr. J. H. Abbot was appointed Recording Secretary pro tem.

Professor Cooke exhibited and described some apparatus

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