I have alluded in this essay to the fact that the eocene and miocene are not connected by a single species common to both. It is equally remarkable that very few are common to the miocene and the newer deposits, and they, with one exception, are recent species. The conclusions derived from my investigations are, that the American tertiaries are of the eras of the eocene, miocene, and post-pliocene, and that the newer pliocene is either wanting, or has not yet been observed. In concluding this brief sketch of a portion of the tertiary region, I will take occasion to remark, that it is my intention when I have fulfilled my obligations to the State of New-York, in publishing the organic remains in connection with its geological survey, to investigate the Atlantic tertiaries more thoroughly, and to submit the results of my labors to the National Institution. In the mean time, gentlemen who reside within the limits of that extensive district would contribute greatly to the advance of American geology, if they would send to the National Institution specimens, in good condition, of all the various organic remains on their plantations. DESCRIPTIONS OF NEW TERTIARY FOSSILS. LOWER TERTIARY OR EOCENE FOSSILS. OSTREA.-(Lin.) Ostrea sellaformis, pl. 1, fig. 1.—This singular oyster, the history of which I have briefly given, appeared so important, in a geological point of view, that I have here introduced a figure of the species, although it had been published, in 1832, in my "Fossil Shells of the Tertiary Formations," page 27, pl. 13, fig. 1, 2. The figure now given is from a much more perfect specimen, which I found on James river, Virginia, a few miles below City Point. SYNONYMES. Ostrea radians, (nob.)-Fossil Shells of Tertiary Formation, pl. 13, fig. 1, (upper valve.) Ostrea semilunata, (Lea.)-Contributions to Geology, pl. 3, fig. 69, (young.) Do. do. fig. 70, (young lower valve.) Having carefully studied this species in all stages of growth, in several localities, the above synonymes are undoubtedly correct. PHOLADOMYA. Pholadomya marylandica, pl. 1, fig. 3.-Ovate, profoundly ventricose, with coarse, irregular, concentric lines and furrows, and obsolete, rather distant, radii; summit of umbo prominent. Locality: Piscataway, Prince George's county, Maryland. PHOLAS. Pholas petrosa, pl. 2, fig. 4.—Ovate-acute; anteriorly profoundly ventricose; radii sharp and numerous; dorsal margin obliquely rectilinear from the summit of the umbo; base obliquely subrectilinear; posterior side produced, cuneiform. Locality: Occurs with the preceding species. MEDIAL TERTIARY SPECIES. ISOCARDIA.—(Lam.) Isocardia Markoči, pl. 2, fig. 1.-Suborbicular; length and height nearly equal; inflated; umbo very prominent, and the beaks profoundly incurved; posterior mar gin direct, arched above, nearly straight below, and obtusely angulated at its junc. tion with the base; base regularly, not profoundly arched; posterior slope slightly sinuous. Locality: Captain Hance's farm, Calvert Cliffs, Maryland. This beautiful species is easily distinguished from I. rustica, (I. fraterna, Say,) by the much more prominent umbo, and greater curvature of the beak, and in being proportionally much shorter. The young shells of the two species are widely unlike each other in outline, this species being round, and the rustica of a long, ovate figure. Deshayes considers the I. fraterna, (Say,) to be identical with I. cor. Upon com. parison, the latter was found to have a far more profound arch or rotundity to its base, as well as much greater curvature of beak; but the difference in the young shells, of either species, is so profound, that any idea of their identity would be instantly abandoned by comparison. Mr. Markoc obtained three or four valves of this shell, and one specimen with connected valves, and I have much pleasure in dedicating the species to him, as a slight tribute of respect for his talents, zeal, and most generous devotion to sci ence. PECTEN (Lam.) Pecten Humphreysii, pl. 2, fig. 2. Suborbicular, inferior valve convex; superior flat, and with about seven remote, narrow, convex ribs, and concentrically wrinkled; towards the apex is a concave depression; ears equal, sides direct and straight; infe. rior valve with the ribs wide, approximate, plano-convex and longitudinally striated; one of the ears emarginate at base. Localities: Near Fairhaven, Anne Arundel county, Md. Mr. Wilkinson's farm, in Calvert county. I am indebted to Dr. Humphreys, of Annapolis, for the loan of the specimen figured, that which I found at Fairhaven being too imperfect for the purpose. I gladly attach the name of this gentleman to the species, in consideration of his love of and proficiency in scientific pursuits. Of two specimens in the collection of the college at Annapolis, the largest mea. sures three inches from beak to base. DISPOTEA.—(Say.) Dispotea constricta, pl. 1, fig. 2.—Shell irregular, elevated; laterally compressed, marked with simple lines of growth; apex prominent, with one or two minute volutions; diaphragm very profound. Locality: Captain Hance's Landing, Calvert Cliffs, Maryland. SCALARIA.-(Lam.) Scalaria expansa, pl. 2, fig. 3.—Shell acutely ovate, moderately thick, with numerous robust recurved ribs, twelve in number, counting from the summit of the aperture to the reflected lip, inclusive; whirls profoundly ventricose at the sides, somewhat flattened above; four or five in number. Locality: St. Mary's river, Maryland. Two specimens of this fine Scalaria were obtained by Mr. Markoe, and none other is known to have been discovered. BUCCINUM.—(Lam.) Buccinum integrum, pl. 2, fig. 5.-Shell short, subfusiform or elliptical; smooth; destitute of ribs or striæ; spire conical, the volutions convex; aperture elliptical, about half the length of the shell; columella thick; labium reflected. Localities: St. Mary's river and Calvert Cliffs, near the mouth of Patuxent river. SCUTELLA.—(Lam.) Scutella Aberti.-Discoidal, orbicular, very much depressed, but swelling towards the middle, and depressed at the apex; diameter five and a half inches. Locality: Patuxent river, St. Mary's county, Maryland. This large Scutella is very abundant; but those I have, at present, are too imper. fect for minute description. A figure of it will be published when specimens in better condition shall be obtained. It is dedicated to my scientific friend Colonel J. J. Abert, of Washington, whose name it gives me great pleasure thus to connect with the tertiary rocks of Maryland. DESCRIPTION OF A NEW EXTINCT SPECIES OF DOLPHIN; FROM MARYLAND. By R. HARLAN, M. D., F. L. S. Lond., Corresp. Member Nat. Institution. ORDER CETACEA. GENUS DELPHINUS. D. Calvertensis. This interesting fossil consists of the skull, nearly complete, densely petrified, very weighty, tinged of a deep, black, ferruginous color; characteristic marine fossil shells adhere to its base. A portion, tested with a solution of muriatic acid, deinonstrated the absence of animal matter. The external border of the superior maxillary bone is slightly broken on each side. Its discovery is due to the active researches of Mr. Francis Markoe, Jun., Corresponding Secretary of the National Institution, who obtained it from the Calvert cliffs, on the right bank of the Chesapeake bay, State of Maryland, along with other characteristic fossils. We refer, with confidence, to the preceding memoir by Mr. Conrad, for the details of this tertiary deposit. Many other osteological remains, of an interesting kind, have recently been obtained by Mr. Markoe from the same locality. The present specimen belongs to Cuvier's first sub-genus, or “les Dauphins à long bec." On comparison with the numerous species of living dolphins, it is found distinct from all of them. It approximates the Delphinapterus leucoramphus, of Peron, but differs in its various measurements, number of teeth, and in the arrangement of the palatine bones. It is unique hitherto in America. Indications of the existence of this genus, in a fossil state, occur occasionally in the geological reports of the State of Maryland.† Four species of fossil Delphinus have been described by Cuvier, (ut supra.) The first consists of a nearly complete skeleton, discovered by M. Cortesi, on the Appenine hills, south of Fiorenzuola. The second species consists of portions of the upper and lower jaws of a Delphinus, disinterred from a falunière, (marine debris,) in the department of Landes, noticed by Cuvier under the name of "Dauphin à longue symphyse de la mâchoire inférieure," ut supra, page 312. Third species, also from the same locality, with marine shells, consisting of a portion of the lower jaw. It is closely allied to the common dolphin, or D. delphis. * Vide Cuvier. Ossemens Fossiles, vol. 5, part 1, page 289, plate 21, figures 5 and 6; edition 1823. "In an essay, On the Physical Geography of Maryland, which I furnished in 1837, to the Transac tions of the Maryland Academy, (says Dr. Ducatel, Geologist of the State of Maryland,) I took occasion to say, in referring to the fossilliferous deposits of the tertiary formations of the State, that the most constant attendants upon these marine shells are the ribsand vertebra of a species of Delphinus, the palatal bones of some fish, and a great number of shark's teeth of all sizes.' In the same essay, alluding to the living genera of marine animals that are found in the Chesapeake bay, I say, 'The largest aquatic residents of the Chesapeake bay, at least in the portion of it within the limits of Maryland, are the por poise, (Delphinus phocœna,) and the sturgeon, (Acipanser lavirostrum,) although occasionally some of the smaller cetacea venture nearly all the way up in pursuit of their prey, during the spawning season of the herring and shad; several individuals of the beluga whale, (Delphinus, leucas,) having been caught in the spring of the last year,' &c. The skeleton of the last mentioned is now in the Baltimore Museum.” 17 No. 2. A fourth species, consisting of a portion of the superior jaw, has been found in the calcaire grossier, in the department of Orne. M. Cuvier has been able to satisfy himself that all these species are distinct from each other, as well as from the living species. The specimen before us bears the nearest comparison with the first of the above named species, but is sufficiently distinguished by the larger size, relative proportions, and number of teeth of the Appenine species. Description of D. Calvertensis.—In general outline, resembling other skulls of this genus. The head is proportionably narrower, and snout more elongated, than the Italian specimen with which I have compared it. The occipital and temporal ridges are strongly developed, indicating muscular strength, especially of the jaws. We find similar indications in the remains of the teeth, which have been large and robust. There are ten sockets remaining on the right side, with the teeth broken off at the rim. These organs approximate each other. The ten sockets include a line four and a half inches long. There has been about one and a half inches of the end of the snout broken off, which would afford room for two or three more teeth-making twelve or thirteen, in all, on each side. The pyramidal eminence, anterior to the posterior nares, on the palatine surface, is strongly pronounced. It terminates opposite the last tooth. The excavations or longitudinal grooves, on each side of the upper portion of this eminence, are unusually deep. The palatine surface is slightly convex transversely. Above, the head is narrower across the occipital ridges than other allied species, and narrower than the transverse diameter of the base of the skull. The ossa nasi are longer than broad, and convex. Tho atlas vertebra adheres to the occiput, above the condyles. It measures, across the transverse processes, five inches; transverse diameter, three inches; and the ring is about one inch thick. In the following admeasurements, one and a half inches must be considered as the length of the last portion of the extremity of the snout. Dimensions.—Total length of head, from the temporal crest to the presumed extremity of the jaw, From the anterior borders of the spiracles to the presumed ex. tremity of snout, Breadth of skull above, across the occipital crests, Breadth at base, between the temporal bones, Longest diameter of largest tooth at the socket, 17 inches. measure. The head of the Appenine species is one foot, ten inches, nine lines long, French The spiracles are one foot nine inches, from the extremity of the snout. The accurate figures which accompany this description, will render further de. tails unnecessary. Geological Series: Middle tertiary of Maryland. Description of the Plates. Figure 1.-Basal view of the skull. |