Part 7

It gives me great satisfaction in being able to describe, and to present to naturalists a good cast of this Calymene, which has excited for a long time so much interest and perplexity. The original fossil from which our plaster model was made is now deposited in the cabinet of the Albany Institute, and is the identical specimen from which a cast was long since made, by Dr. Hosack of New York, a specimen of which he sent in July, 1819, to the Royal Academy of Science, in France. Professor Brongniart referred the animal from which this model was taken, though with much hesitation and doubt, to the species, Calymene Macrophthalma. He remarks concerning it, "Il est beaucoup plus gros que les autres individus, et a prés de dneuf centimètres de longueur. C'est avec doute que je rapporté cette empreinte tres-peu nette à l'espèce actuelle; mais malgré ses formés obtuses, et l'absence de tout detail, elle est si remarquable par la grosseur de ces yeux et par le prolongement de son bouclier qu'on peut présumer qu'elle appartient an calyméne macrophthalme, et avec d'autànt plus de probabilité qu'elle vient aussi des Etats Unis d'Amérique. Elle a été trouvée, suivant M. Hosack, dans un schiste." We have seen the cast alluded to in the above note, and are not at all surprised at the uncertainty which it has occasioned. The apparent prolongation of the buckler is entirely occasioned by the loss of a small fragment from that portion of the head. The form and position of the eyes, further distinguish it from any of the numerous specimens of C. Macrophthalma, that we have examined. The raised lines which we have noticed as intersecting the costal arches of the lateral lobes are remarkable, though they may have been produced by accidental fissures in the epidermal covering of the animal. The head of the C. Macrophthalma is always marked by minute and prominent granulations, like shagreen--nothing of this kind appears on the buckler of the C. Anchiops.

I am informed by my friend, Dr. T. R. Beck, to whose liberality I owe this interesting species, that it was found in Ulster county, New York. It was supposed by Dr. Hosack, to have been discovered in the vicinity of Albany. Respecting the locality and geological relations of this trilobite, Professor Brongniart remarks, "un modéle en plâtre de trilobite envoyé à l'Académie des Sciences, en Juillet, 1819, par M. Hosack, et que j'ai rapporté, autant que la chose était possible, et toujours avec doute, au calyméne macrophthalme, a été trouvé dans le territoire d'Albany, êtat de New York. Or, les environs de cette ville sont indiqués, sur la carte géologique de M. Maclure, comme formés de terrains de transition. M. Hosack dit qu'il a été trouvé au milieu d'un rocher ardoisé, c'est à dire, dans un schiste probablement analogue à celui des environs d'Angers, qui renferme les Ogygies, et ce trilobite ce rapproche un peu de ce genre par la grosseur des tubercules qui recouvrent les yeux on en tiennent la place." The rock in which the Calymene Anchiops is found, appears to be a clay slate.

Calymene Diops. Green. Cast No. 8, and fig. 2.

Clypeo lobato plano; rugis tribus in lateribus frontis; tuberculis oculiformibus, eminentissimis et duplicibus; articulis octodecim; cauda rotunda.

This species is very distinct from every other Calymene that we have seen. The outline of the buckler is lobate lunate; the front is very convex, and a good deal elevated above the cheeks or sides, from which it is divided by a deep furrow; on the posterior margin of the front on each side, close to the groove there is a prominent circular tubercle, before which there are three small transverse wrinkles. The cheeks are subtriangular; the oculiform tubercle is near the posterior superior angle, and is only separated from the tubercle on the front, by the furrow or groove, so that the animal seems to have had double eyes on each side; there are two curved lines on each side below the eyes, crossed near the front by a deep short canal. The middle lobe of the abdomen and tail is rather longer than the lateral lobes, and is rounded and very prominent throughout. It is composed of 18 articulations, seven of which appear to belong to the tail; it is, however, somewhat difficult to define the length of the tail with precision. The costal arches of the lateral lobes, particularly those near the tail, are bifurcate. Length almost three inches.

The original fossil, from which the cast was taken, is in the New York Museum. I am indebted to Mr. Rubens Peale, the liberal proprietor of that flourishing and important institution, not only for the use of it in this Monograph, but also for some valuable information relating to other species. The precise locality of Mr. Peale's specimen is not known, but in the cabinet of J. P. Wetherill, Esq., there is a fine head of the C. diops which was found in the State of Ohio. Both specimens are mineralized by the same kind of soft grey coloured limestone--and I have but little doubt that they were derived from the same place.

Calymene Macrophthalma. Brongniart. Cast No. 9.

Clypeo antice, caudaque postice attenuatis, oculis magnis exsertis.

This species, according to Al. Brongniart, who first described it, is remarkable for the magnitude and protuberance of its eye-shaped tubercles, and by the prolongation of the anterior portion of the buckler, in the form of a snout.

The back is marked by 12 or 13 articulations, which are thicker than those of the tail. The tail is short, pointed, and without expansion.

The middle lobe, or front of the buckler, in this calymene, is said by Brongniart to be marked on its sides by three oblique plicæ or wrinkles, but we have not been able to discover this character in any of the specimens to which we have access; neither do they exhibit any remarkable prolongation in the anterior portion of the buckler, as stated in his specific character. The specimens which we have examined, agree pretty well with the representation he has given of the C. Macrophthalma, Plate I. fig. 5. A. B. & C. made from a drawing by Mr. Stokes, from a fossil found in Coalbrookdale (Eng.).

This trilobite is common in several parts of the United States. According to Dr. J. E. Dekay, the C. Macrophthalma is found on the Helderberg mountains, near Albany, and at Coshung creek, not far from Seneca lake, in the State of New York. It occurs also at Leheighton, in Pennsylvania--at the Falls of the Ohio, and at several other localities. We have examined a number of specimens of the C. Macrophthalma, contained in the rich cabinet of fossils, in the Academy of Natural Sciences, and have never seen any individual which resembles the fig. 4, Plate I. of Brongniart; and in no instance is the front of the buckler marked by three oblique folds, a character stated as peculiar to this species. The C. Macrophthalma, (variety) occurs in large quantities in Leheighton in Pennsylvania, and we are indebted to Mr. D. Keim, for some fine specimens from that locality.

The authority of Professor Brongniart is sufficient to place the C. Macrophthalma among the species of the United States, though we have been unable fully to identify it with his description. He received a specimen, transformed into red jasper, from Prof. Ducatel, said to be found in the United States--no precise locality is given. Our model represents the animal which is supposed to be the one intended by Brongniart as the C. Macrophthalma of North America. It is, in our opinion, a variety of the C. Bufo. There can be no doubt that several species have been confounded under the name of C. Macrophthalma.

The following extract of a letter from Professor Ducatel to the author, referring to the locality of this species, will be read with interest.

"I cannot be positive as to my recollection of the locality of the fossil referred to by Brongniart and yourself, but believe it is one of several found by my friend Dr. M'Culloh, in the neighbourhood of Berkley Springs, Virginia. I regret that I have not in my possession another specimen to present to you."

Calymene Bufo. Green. Cast No. 10.

Clypeo rotundato, convexo, punctato; abdominis articulis sexdecim; cauda attenuata; corpore plano.

Buckler semilunate, front very large, rounded before and arcuated at the insertion of the middle lobe; surface convex, and marked with numerous depressed pimples. Mouth large, lunate, resembling that of a toad or frog, with a narrow raised rim on the upper and under lip. Below the chin there are no pustulations. Cheeks small, triangular, and separated from the front by a deep, rectilinear furrow; the eyes in our specimen are much injured, but they are large, and near the upper angle of the cheeks. Middle lobe with a series of distinct double articulations. Lateral lobes wider than the middle lobe, ribs deeply grooved near their insertion; articulations of the abdomen twelve; of the tail ten. Length four inches and a half; breadth of the buckler nearly two inches.

This fossil was presented to me some time since by Thomas P. Johnson, Esq., who mentioned that it was found in New Jersey, but that he could not learn its precise locality. Near Patterson, in that State, some trilobites have been discovered--perhaps the C. Bufo may have been derived from that locality. It is composed of a dark greyish limestone, easily cut with a knife.

Calymene Bufo. Variety, Rana. Cast Nos. 11 & 12.

This fine specimen differs from the one above described, in having the front of the buckler rather smaller, and of a different contour. The whole of the shell is also covered with granulations, which only appear on the head of the other; this, however, may be only an imperfection in the specimens in our cabinet.

I am indebted to the Albany Institute for the originals of the models Nos. 11 & 12. They were found at Seneca, Ontario County, New York, in dark, slaty limestone, which also contains cubical crystals of iron pyrites. A fortunate blow of the hammer has fractured the rock which contains this trilobite, so neatly, as to present us at the same time with the petrified animal in an almost perfect state, and also with the mould or matrix in which it was imbedded. This arrangement is beautifully illustrated by our models.

Genus Asaphus. Brongniart.

This genus derives its name from the Greek word Ασαφης--obscure. It embraces perhaps more species than any other genus of the family of trilobites. About twenty have already been discovered. Most of them are very characteristic and can easily be determined, but as the genus Asaphus, is intermediate between Calymene and Ogygia, it is sometimes a little difficult to decide the genus to which the inosculating species on each side, belongs.

In general, the Asaphs may be known by the body being very much depressed, and by the membranaceous development, which extends beyond the lateral lobes. The middle lobe of the abdomen, is rarely more than one-fifth the width of the body. As the abdomen and tail of the Asaph are the only portions of the animal commonly found entire, the distinctive characters of the genus above given, may generally be ascertained.

Professor Brongniart remarks, that the ribs of the Asaph, which correspond in number and position to the articulations of the middle lobe, "are sometimes simple or undivided, at least in the post abdomen, but that they are always bifurcated in the Calymene" As far as our observations have extended, these remarks do not apply either in the one case or the other.

The head or buckler of the Asaph, is not so deeply divided into three lobes as the Calymene; they are, however, quite distinct. The oculiferous tubercles are in some species exceedingly well marked by a reticulated structure.

This genus often occurs at the same localities with the Calymene, though in some instances it seems to occupy rocks peculiar to itself. Dr. John Bigsby, in his list of organic remains occurring in the Canadas, states, that he never found a single species of the genus Calymene, on the north side of the River St. Lawrence, although the Asaphs were very abundant. In his Sketch of the Geology of the Island of Montreal, he however observes: "Of Trilobites, the Asaph genus is the most abundant, they approach nearest the species caudatus, of Brongniart. I have found no entire Calymene, but many bucklers or heads of the Blumenbach species, some of them an inch and a half in diameter. They are found whole in considerable numbers in the vicinity of Quebec."