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POPULAR SCIENCE REVIEW. 
furnished evidence of the footprints of no less than thirty-two 
species of bipeds, and twelve quadrupeds. Thirty are believed 
to be birds, four tracks of lizards, two of chelonians, and six of 
batrachians. The tracks have been found over an extent of 
nearly eighty miles north and south, and in more than twenty 
places. They are repeated through a succession of beds attain- 
ing at some points a thickness of more than 1,000 feet, and 
occupied, doubtless, thousands of years in formation.* 
More than 2,000 impressions have been examined by Prof. 
Hitchcock : — 
44 The bipedal impressions are for the most part trifid , and 
show the same number of joints as exist in the feet of living 
tridactylous birds. 
44 Such birds have three phalangeal bones for the inner toe, 
four for the middle, and live for the outer one, but the im- 
pression of the terminal joint is that of the nail only. The 
fossil footprints exhibit regularly, where the joints are seen, the 
same number ; and we see in each continuous line of tracks the 
three-jointed and five-jointed toes placed alternately outwards, 
first on one side and then on the other. In some impressions, 
beside the three toes in front the rudiment of the fourth toe is 
seen behind. 
44 It is not often that the matrix has been fine enough to 
retain impressions of the integument or skin of the foot ; but 
in one specimen found by Dr. Deane at Turner’s Falls, on the 
Connecticut River, these markings are well preserved, and have 
been recognised by Prof. Owen as resembling the skin of the 
ostrich, and not that of reptiles. 
44 Among the supposed bipedal tracks the feet of a single 
distinct animal only has been observed, in which there are four 
toes directed forwards. In this case a series of four footprints 
is seen, each twenty-two inches long and twelve wide, with 
joints much resembling those in the toes of birds.” f 
Assuming the correctness of the opinion long ago expressed 
by Dr. Mantell, and subsequently by Prof. Leidy of Phila- 
delphia, Prof. Huxley, and others, that Iguanodon , Hadro- 
saurus , as well as other of the monstrous land-lizards of the 
Secondary rocks, may have supported themselves, for a time at 
least, upon their hind legs, then some of these remarkable 
bipedal tracks may be referred to the Reptilia.J 
The discovery by Mr. S. H. Deckles, F.R.S., in the slabs of 
ripple-marked sandstone, near Hastings, of pairs of large three- 
toed footprints of such a size and at such a distance apart, that it 
* Hitchcock, 1848. “Mem. Amer. Acad.” new series, vol. iii. p. 129. 
f Lyells “ Elements,” 6th edition, 1865, p. 453. 
\ See “Quart. Journ. Geol. Soc.” 1874, vol. xxx. p. 8. 
