In the fossils of this genus yet noticed, thestalks have been very short; and although numerous fragments of these have been found, it was not certain that they belonged to the heads, the portions of stalk attached generally not exceeding an inch or two; whereas in those which are the subject of the present paper, we see stems of considerable length, frequently extending four or five feet. All the fossil alcyonic heads which have been described as approaching to a globular form, are characterised by a considerable opening in the end; but the species we have been considering has no such structure. From the circumstance of the heads appearing in shape much like the closed buds of the tulip, and from their being attached to long smooth stalks, perhaps the name Tulip Alcyonium may not be improperly applied to this species.
In the stratum containing the white radiated circles, and frequently in the same block with them, I noticed another species of cylindrical and tubular organic body, somewhat resembling them, but differing essentially in some particulars. Fig. 14, Pl. 29, exhibits the appearance they assume. They are usually about half an inch in diameter, the inside nearly cylindrical, or rather slightly elliptical, and the body much thicker on one side than on the other so as to make the form of the outside very irregular; but they never have the radiated character of the others. They do not vary much in diameter, and are frequently several feet in length. They do not taper, and I found no branching nor bulbs. Their substance is calcareous, of a whitish colour, and the matter with which they are filled is the same with that in which they are enveloped.
Fig. 15, Pl. 29, represents a fossil organized body, which I found to occur frequently in the stratum of blue marl immediately under the sandstone, or rather in the part where both these strata pass into each other.