ON THE PROGRESS AND PRESENT STATE OF ORNITHOLOGY. 211 



Treatise,' pi. 26 a and b, and 'Ann. So. Nat.' ser. 2. vol. v. p. 154.) Two ques- 

 tions arise in connexion with these impressions ; first, whether they are really 

 produced by birds ; and secondly, what is the age of the rock in which they 

 are found. The first question seems to be now finally settled in the affirma- 

 tive, some of the impressions being so nearly identical with those of certain 

 existing Grallatores and Rasores as to convince the most incredulous. The 

 footmarks are evidently due to Birds of several distinct genera, some of which 

 present structures as anomalous as those found in the Reptiles and Fish of the 

 same remote epoch. The greater part, however, appear clearly referable to 

 Wading Birds allied in structure to the CharadriidoR or Scolopacidce. Some 

 are of such a gigantic size that we can only seek their affinities among the 

 StrutJiionidce, and others appear to have had the tarsi clothed with feathers 

 or bristles, a character which would exclude them from the Grallatores as at 

 present defined, though, judging from the impressions made by living birds 

 in snow, I think this appearance may possibly be due to the trailing action of 

 the foot before it takes its hold of the ground. One very remarkable form 

 (if really belonging to a bird) has the outer and middle toe united as in the 

 so-called Syndactyles of Cuvier, and is further distinguished by all the four toes 

 pointing forwards (neither of which characters are in the existing fauna ever 

 found in ambulatory birds). Such anomalous structures however (reasoning 

 from the analogy of the fish and reptiles of the older rocks) appear rather to 

 confirm than to disprove the genuineness and antiquity of these Ornithich- 

 nites ; and as there is no other known class of animals to which they can by 

 possibility be referred, it would be very unphilosophical to deny them to be 

 the footmarks of birds, to which they bear so strong a resemblance. 



In his ' Report on the Geology of Massachusets,' Dr. Hitchcock has de- 

 scribed no less than twenty-seven species of these footmarks, and in the ' Re- 

 ports of the American Association of Geologists and Naturalists, 1843,' he 

 has added five more. (See also Silliman's Journal of Science, Jan. 1844.) 

 One of these much resembles the footprint of a Fringilla, others are similar 

 to those of Fulica. In all these impressions, the phalanges of the toes obey 

 the same nuraei'ical law which prevails, with hardly an exception, in the feet 

 of existing birds*. They are accompanied in some cases by reptilian foot- 

 marks resembling those of Chirotherium, which are at once distinguished 

 from the ornithic impressions by being quadruped, and by the forward posi- 

 tion of the thumb. 



Granting then that we have here the genuine indications of an ancient 

 ornithological fauna, of which no other traces than these footmarks have been 

 found, we have next to consider the geological age at which they were formed. 

 Now it appears that the phaenomena of superposition merely show that this 

 deposit is intermediate between the Carboniferous and Cretaceous series. 

 Could we have availed ourselves of such a latitude for speculation, the ana- 

 logy of the oldest fossil birds found in the eastern hemisphere, would lead us 

 to adopt the latest period within the above limits for fixing the age of these 

 impressions. It has been announced however, both by Dr. Hitchcock and 

 by Mr. Lyell (Proc. Geol. Soc. vol. iii. p. 796), that the only recognizable 

 organic remains discovered in this deposit are Fish belonging to the genera 

 Palceoniscus and Catopterus, and as these genera have never been found 

 above the Triassic series, we are compelled to follow Dr. Hitchcock in refer- 



* The remarkably simple law referred to is this : that if we consider the metatarsal spine 

 of certain Rasores (and which is wanting in all other birds) as the first toe, the hind toe as the 

 second, and the inner, middle, and outer toes as the third, fourth, and fifth, the number of 

 phalanges is found to progress regularly from one to five. The only exceptions are in the 

 Caprimulgidee, Cypaelus, and one or two others. 



p2 



