70 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. I. 



strata, brought conviction to my mind. Professor Hitch- 

 cock's last memoir on this subject embraces figures, and de- 

 scriptions of footprints, which he considers as referable to 

 twelve kinds of quadrupeds ; viz. four probably Saurians, 

 two Chelonians, and six Batrachians. The bipedal imprints 

 belong to eight species of thick-toed tridactylous birds; 

 fourteen to narrow-toed tridactylous or tetradactylous spe- 

 cies ; two are probably of bipedal batrachians ; and eight 

 are not determinable. 



I have described the bipedal imprints as those of birds, in 

 conformity with the opinion entertained by the most eminent 

 observers, who have carefully investigated the phenomena on 

 the spot. 



IMPRESSION OF THE SKIN OF THE TOES. Unfortunately, 

 the footprints very rarely exhibit any traces of the struc- 

 ture of the dermal integument, or skin, a character which 

 would yield important evidence as to the reptilian or or- 

 nithic relations of the original. It may, therefore, be in- 

 teresting to state that on a slab collected by Dr. Deane, and 

 presented to me, there are two or three foot-marks with distinct 

 impressions of the skin of the under surface of the toes ; 

 and this structure appears to resemble that of the Ostrich. 1 



1 This specimen is in my possession ; the following note from Dr. 

 Deane accompanied it : 



" The slab is about two feet in diameter, and half an inch in thick- 

 ness. On the upper surface there are two rows of small elegant foot- 

 marks, of the species termed by Professor Hitchcock Ornithichnites 

 gracillimus ; one row consists of five, and the other of six consecutive 

 impressions. There is also a row of four footprints of a much larger 

 species, the 0. fulicoides. These are arranged around the circum- 

 ference of the specimen, and their alternate order proves that they 

 have been impressed by the same individual. There is a rare pecu- 

 liarity displayed in these larger impressions that adds greatly to their 

 interest; it is the markings of the papillae, and folds of the cutaneous 

 integument, which are very distinct; and this character I have only 

 observed in two other examples. The papillee may be seen most dis- 

 tinct in the first, second, and fourth footstep ; particularly in the 

 last of the series, on the top of the slab. The three tracks em- 

 brace fifteen impressions, and exhibit the articulations of the toes 

 perfectly. The surface of the stone is pitted by rain-drops, from a 

 shower which must have fallen before the birds walked over the soft 

 mud, and made the foot-prints. There are also indistinct traces of 

 the trails of worms, and of an Annelide. On the reverse of the 

 slab there are the casts of four consecutive impressions of Ornithich- 

 nites gracillimus; and a row of two, of dimensions intermediate 

 between those of the preceding varieties." 



