Mr. Pierce's discovery is not less interesting; and we presume he will be deemed correct in the opinion, that pure native carbonate of magnesia has not been discovered before. The serpentine of Hoboken, then, is memorable for affording these two new species. ART. V. _Native Copper._ In Bruce's Journal, (Vol. I. p. 149.) mention is made of a remarkable piece of native copper, found near New-Haven many years ago, and weighing about 90lbs. We have now to add, (and the fact is, indeed, mentioned in Cleaveland's Mineralogy,) that another piece has been recently found half a mile west of the Hartford turnpike road, opposite the town of Wallingford, and twelve miles from New-Haven. It was turned up in ploughing to repair a road. The country is of the secondary trap formation, and the rocks, at the particular place, are the old red sandstone of Werner, which here occupies the plains, and runs under the trap. The piece weighs almost six pounds; it is fine virgin copper, with rudiments of large octahedral crystals of native copper upon its surface, which is more or less incrusted with green carbonate of copper and ruby oxid, very much resembling that of Cornwall: the ruby oxid is particularly remarkable in the cavities of the piece. As it was found within three or four miles of the place where the large piece of ninety pounds weight was discovered, and as copper is known to exist in many places in these hills, the facts should be kept in view, and may lead to something of importance. ART. VI. _Petrified Wood from Antigua._ The mineralogy and geology of the West-India islands has been, as yet, but little explored. The scientific world has, however, been favoured with some interesting articles from the pen of Dr. Nugent; and we are informed that he has described also the geology of the island of Antigua. We have recently become acquainted with one interesting production of this island, and without waiting for Dr. Nugent's account, (which we believe has not yet reached this country) we shall lay it before our readers. We are under obligations to Mr. Pelatiah Perit, of New-York, for a collection of specimens of silicious petrifactions of wood from Antigua. Their characters are indubitable; the distinct ligneous layers corresponding with the annual growth, the medullary prolongations, the knots formed by branches, the cracks and the bark, are all distinctly visible. Some of the pieces are ponderous portions of large trees.