60 ICHNOGRAPHS OF THE 



had a tail. If this grooved furrow shall be found to have been produced by a tail, it 

 will settle the fact that the impressions were not due to birds. But a still more decisive 

 circumstance lies in the discovery of ornithic footprints and reptilian footprints combined ; 

 that is to say, the posterior feet were ornithic, and the anterior reptilian. This extra- 

 ordinary combination is the first fact that has ever thrown a doubt upon the ornithic 

 origin of the tracks. It is certain that an animal existed having the feet both of birds 

 and reptiles; a quadruped, with anterior feet of five toes each, and posterior feet of three 

 toes. Separated from the reptilian impressions of the fore feet, no one could hesitate, 

 for a moment, to pronounce the posterior imprints ornithic, upon the strict laws o( 

 analogy." 



Further than this; in some remarks in his .Memoir, Dr. Deane implies, that in the 

 contingency of certain discoveries (just such as have been since made), the whole theory 

 of the ornithic character of any of the footprints would be overthrown. It seems proper 

 to quote here this remarkable prediction, now likely, in the opinion of the writer, to be 

 verified. Already has an article appeared in Silliman's Journal sustaining the view that 

 none of the footprints were made by birds; and this by Roswell Field, whose oppor- 

 tunities for observation and study are not surpassed by those of any other man. Dr. 

 Deane, referring to Plates 31 to 34 inclusive, says : •• The singular resemblance of the 

 posterior feet, in these remarkable forms of the quadrupedal footprints, to those of ornithic 

 varieties, is a circumstance of significant meaning, associated, as they are. with footprints 

 of unquestionable reptilian type. If it shall be proved by future discoveries that the 

 animals making these complicated impressions possessed the additional power of walking 

 upon their posterior feet alone, the ornithic theory of the footprints would be settled in 

 a summary manner, impregnable as it now seems to be." 



The substance of this he again repeats in his description of Plates 33 and 34. 



Now, with the purpose of giving to the reader an important fact in relation to the 

 animals that have left their impressions upon the sandstone, as well as to show how 

 much reason Dr. Deane would have found, had he lived, to assume the ground that 

 none of the footprints were made by birds, it may be stated that Mr. Roswell Field has 

 now in his possession a slab with a series of tracks upon it, most of which appear to 

 have been made by a bird, as clearly so as any that are found. The footprints follow 

 each other in the requisite order, the right alternating with the left, and they have all 

 the usual ornithic characters in the number of toes impressed, and in the number of 

 phalanges of the several toes. In the progress of the animal over the surface, he seems 

 at one place to have stopped; for the footprints, instead of following each other in the 

 manner of the first, are brought side by side, or nearly so ; and here they exhibit them- 

 selves, not, however, as before, but as having a long heel on which they rest, precisely 

 as do the marsupials of our day, and as the animals did that made the impressions on 

 Plates 31 and 33. Yet more. Just in advance of these impressions are two others, 



