A Pictorial Atlas of Fossil Remains, consisting of coloured illustrations selected from Parkinson's "Organic remains of a former world," and Artis's "Antediluvian phytology."

by Gideon Algernon Mantell

3. The Phragmocone (d), or chambered, siphunculated (c), internal shell; the apex of which occupied the alveolus (g) of the guard, and the upper part constituted a capacious chamber, from the basilar margin of which proceeded two long, flat, testaceous, processes (a, a,).

These structures comprise all that are at present known of the animal to which the fossil commonly called "Belemnite," belonged.

Of the Belemnoteuthis, the cephalopod which Professor Owen considers to be a Belemnite, many examples of the body with eight uncinated arms and a pair of long tentacula, and with an ink-bag, and palleal fins, have been discovered. The osselet of this animal, like that of the Belemnite, has a fibro-radiated structure, investing a conical chambered shell; but this organ, for reasons fully detailed in the memoir, could never have been contained within the alveolus of a Belemnite.

No certain evidence has been obtained of the occurrence of an ink-bag in natural connexion with a Belemnite.

Diagram of the known Structures of the Belemnites Puzosianus, from Trowbridge.

a, a, dorsal processes.
b, b, the receptacle.
c, c, the siphuncle.
d, d, the phragmocone.
e, the capsule.
f, the inferior end of the phragmocone.
g, the alveolus of the guard.
h, vertical section of the guard.
i, the guard, or rostrum of the osselet.
k, sulcus, or furrow, on the ventral aspect of this species of Belemnite.
l, capsule, or periostricum.
m, the dorsal line.
n, transverse section, showing the fibrous radiated structure of the guard.

In the annexed outline the several parts are represented in their natural relative positions. The capsule, or most external investment, (e) is seen only in section, being removed to expose the rostrum or guard (the fossil body generally known as the Belemnite). The upper three-fourths of the rostrum are also taken away, to show the phragmocone which it originally enveloped. The straight transverse lines denote the chambers of the phragmocone; the latter is seen extending downwards till it terminates in a point or apex; that part of the cavity in the guard is called the alveolus. The siphuncle, or tube which extends through the entire series of chambers, and is situated on the ventral margin, is indicated at c, c. The dorsal processes (a, a) are seen on their inner aspect at the upper part; the diverging lines (m) between them indicate the impressions of the soft parts, of which some traces remain.

[III.] Fossil Remains of Birds.—The Moa, or Dinornis of New Zealand. The bones of birds are of extreme rarity in a fossil state. Throughout the immense series of the palæozoic and secondary formations—the accumulated sedimentary deposits of innumerable ages—no unquestionable indications of the existence of this class of highly organized beings have been brought to light.

In the Triassic, or New Red argillaceous sandstones of the valley of the Connecticut River, in North America, some very remarkable phenomena have, however, been discovered, and which in the opinions of many eminent observers render it highly probable, that at the period when these strata were deposited, numerous birds, some of colossal magnitude, abounded on the then dry land. When slabs of these sandstones are split asunder, or exposed, so as to exhibit the sedimentary surface which separates one layer from another, the foot-prints of many species of bipeds are perceived deeply impressed on the stone, and disposed in such manner as to prove that they are the tracks of animals that walked over the surface of the deposit when it was in a soft or plastic state. The close analogy of these imprints to those of birds' feet, not only in their general resemblance, but also in the disposition of the tracks, and in the relation of the distance of the stride, and the depth and shallowness of the impressions, to the size of the respective feet, tends to corroborate the inference first enunciated by Professor Hitchcock, and subsequently confirmed by other geologists, that these mysterious markings on the rock, are natural records of the existence of various tribes of birds during the Triassic period;[87] but unfortunately the only certain evidence of the correctness of this opinion—remains of the skeletons—is wanting; not a vestige of a vertebrated animal of a higher class than fishes and reptiles has been discovered.[88]

[87] Travels in North America, vol. ii. pl. 7.