66 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. I. 



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 per- 

 fect and distinct specimens have been discovered in the beds 

 at " Turner's Falls," the northern termination of the sand- 

 stones. 



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 and added to the collection in 1844. The foot- 

 tracks are not confined to any particular beds, but are re- 

 peated 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 ob- 

 served, 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 estu- 

 ary; 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. 



