clined edges of primary or palæozoic rocks. These deposits are traversed from north to south, through an extent of eighty or a hundred miles, by basaltic dykes, which have elevated the sandstone beds on the east, and partially overspread them on the west, the strata dipping in the latter direction at an angle of from 20° to 50°; successive layers of sandstone are thus exposed, and accessible along considerable tracts of country. From this circumstance, and from the facility of transport afforded by the proximity of the river, numerous quarries have, for many years, been profitably worked near the water's edge in various localities in the valley of the Connecticut. About fifteen years ago, attention was directed to numerous tracks of trifid imprints which appeared on the upper surface of the sandstone, with the corresponding figures in relief on the under face of the superincumbent layers, and which were thought to resemble the footsteps of gigantic birds. At length some well-marked specimens came under the notice of Dr. Deane of Greenfield, who communicated the fact to Professor Hitchcock (the President of Amherst College), and other naturalists, and the origin of these problematical appearances became a subject of earnest inquiry. Dr. Deane diligently collected specimens from various localities, and Professor Hitchcock scientifically worked out the subject, and in 1836 published the first account of these fossil footprints in the American Journal of Science. To this eminent observer is due the merit of having established, upon scientific grounds, the true nature of these enigmatical inscriptions on the Triassic rocks, and reduced a mass of vague observations and conjectures to a systematic arrangement of the phenomena in question. The foot-tracks are, for the most part, tridactylous (three-toed); but many have a fourth toe directed backwards. Some resemble those made by the feet of small birds, others of birds of moderate size; the greater number, however, must have been made

1 In England, Dr. Buckland was the first to admit the correctness of Professor Hitchcock's interpretation of the facts observed: see Bridgewater Treatise, 1836, vol. ii. p. 39. I must refer the reader for further particulars to "Wonders of Geology," p. 556. Dr. Deane (who first directed the attention of naturalists to the fact) has communicated several interesting memoirs to the American Journal of Science, and the Trans. Acad. Americ. The most complete and scientific memoir en the subject is that by Professor Hitchcock, in Trans. American Academy of Arts and Science for 1848, with numerous plates. See also Sir Charles Lyell's "Travels in the United States,” vol. iii.

F

by bipeds much larger than the ostrich, or any known living types, and are comparable in magnitude with the footsteps of the extinct Moas of New Zealand, of which we shall treat in the next chapter. Tracks of small quadrupeds are oftentimes associated with those of the bipeds, and appear to be referable to reptiles-possibly of the batrachian order, and related to the Labyrinthodon, or Rhynchosaurus. The fossil footprints occur in many localities, extending upwards of eighty miles from north to south, and have been found in New Jersey and Pennsylvania. In general they are abundant wherever extensive explorations have been conducted in the laminated argillaceous sandstones. Dr. Deane states that the most perfect and distinct specimens have been discovered in the beds at "Turner's Falls," the northern termination of the sandstones.

SPECIMENS IN THE BRITISH MUSEUM.-It was from this locality that the three fine specimens affixed to the wall before us were obtained by Dr. Deane, of whom they were purchased by the Author for the Trustees of the British Museum,1 1 and added to the collection in 1844. The foottracks are not confined to any particular beds, but are repeated through the entire series of strata, which in some places attains a total thickness of nearly 1,000 feet.

The laminated structure of the deposits indicates a slow and gradual accumulation of fine sediment, like the deposit of the mud of the Nile; and the period through which the same phenomena were repeated must have embraced thousands of years. But though the vertical extension of the tracks is so great, their horizontal distribution, so far as hitherto observed, is very limited. Professor Hitchcock states that they are generally restricted to a belt of rock only a few yards wide, and which seems to have formed the shore of an estuary; and that along this strand are the footsteps of all the animals that frequented that ancient shore.

I subjoin a figure of one of the small footprints, (Lign. 21,) to show that the structure of the toes is analogous to that in birds; the number of phalanges in the respective digits exactly corresponding; thus there are three in the great or inner toe, a; four in the middle, b; and five in the outer toe, c. The lobes apparent at the junction of the

1 At the cost of £60.

three digits are produced by the distal extremity of the metatarsal bone: the hemispherical and circular spots with

LIGN. 21.-FOOTPRINT OF A TRIDACTYLE BIRD, AND IMPRESSIONS OF RAINDROPS, ON SANDSTONE. CONNECTICUT. (Nat.size.)

which the surface of the stone is sprinkled, are the effect of rain, which must have fallen before the footprint was made.

The following is Dr. Deane's account of the specimens before us :

"It is rare to find a stratum containing these foot-prints exactly as they were impressed by the animals; for they are usually more or less distorted and obliterated by the soft nature of the mud, the coarseness of the materials, and other circumstances, which have partially defaced them; so that although the general form of the foot may be apparent, the minute traces of its appendages are almost invariably lost. In general, distinct evidence of the peculiar phalangeal structure of the toes of birds is wanting, and each toe appears to be formed of a single joint, without the terminal claw. But a few specimens have been discovered in which the true charac

ters of the foot are clearly developed, with its rows of phalanges, and its claws, and integuments. So far as my observations extend, the sharpest impressions are on the shales of the finest texture, with a smooth glossy surface, such as would retain the impressions of rain-drops (as in Lign. 21). The layers of stone do not often present this kind of surface; but recently I have discovered a stratum containing in all more than one hundred most beautiful impressions of the feet of four or five varieties; the whole surface having also been pitted by a shower of rain. The impression of a medallion is not more sharp and clear than are most of these imprints; their remarkable preservation may probably be ascribed to the circumstance that the surface of the stratum was incrusted with a layer of micaceous sandstone, which adhered so firmly that it could not be removed without the laborious and skilful application of the chisel. The appearance of this glossy layer, which is of a grey colour, while the slab is of a dark red, seems to indicate that it was washed or blown over the latter while in a state of loose sand; thus filling up the foot-prints and rain-drops, and preserving them unchanged in the smallest particular; the form of the nails or claws, and joints, and the deep impressions of the distal extremity of the tarso-metatarsal, or shank-bone, being exquisitely displayed. The great slab (Lign. 22), which is about six by eight feet in dimensions, and two inches in thickness, contains above seventy-five impressions. There are five rows of the species called by Professor Hitchcock Ornithichnites fulicoides, of five and six foot-marks each; three rows of the medium size, of four imprints each; one row of the small size, of fourteen consecutive imprints; besides several others, ranging from two to six impressions each. It is worthy of remark, that of these numerous footprints, with but one or two exceptions, two or more nowhere occur on the same spot.” The direction and disposition of these footsteps on the largest stone are shown in Lign. 22; and lines are drawn from one imprint to another in the course of the consecutive tracks, to render the illustration more intelligible. principal tracks on this slab are as follow; viz.

The

10. fulicoides, so named from the resemblance to the footprints made by the recent Cinereous Coot (Fulica Americana). See "Trans. American Geologists," p. 259, 1 vol. 8vo. Boston, 1843.