326 Ornithichnology. 



feathers, as, for instance, the sharp tailed grouse,* (Tetrao phasianel- 

 lus,) and I do not see why such an appendage would not produce pre- 

 cisely the impression on soft mud which the fossil specimens exhibit. 



In comparing the descriptions that have been given of the spe- 

 cies, it is interesting to observe how the length of the step increases 

 in proportion to the size of the foot ; from the huge O. ingens, with 

 a foot sixteen inches long, and a step of at least four feet, down to 

 the O. minimus, with a foot one inch long, and a step between 

 three and five inches. In order, however, to present this corres- 

 pondence before the mind at glance, as well as to give an idea of 

 the peculiarities of the different species, I have prepared the ap- 

 pended " Proportional view of the Ornithichnites." On this the pro- 

 portional size of the different tracks is shown as well as the compara- 

 tive length of the ste])s. The whole is laid down from a scale of 

 five inches to an inch. The plate does not present the appearance 

 of any one specimen ; but a connected view of the results obtained 

 by an examination of all the specimens that have come under my 

 notice. Very few single specimens are as perfect as those here 

 represented ; but a careful examination of various specimens has 

 brought to light new characters, so as to justify me in exhibiting 

 the tracks of as perfect a form as those on the plate. Where rows 

 of several tracks are given on this plate, the toes are represented as 

 turned outwards, and slightly curved, as they are seen in the most 

 perfect specimens. 



The two first species on this comparative view are exhibited in 

 relief; and the others as depressions. This was done in order to 

 give a more distinct sketch of the protuberances on the under side 

 of the toes of the two first species. It should be recollected that 

 such a representation will invert the position of the feet ; so that 

 what appears to be the left one is in fact the right one, and vice versa. 



In the series of figures extending from 1 to 9, and including 16, 17, 

 23 and 24, an attempt is made to exhibit the tracks just as they ap- 

 pear on the rock. Yet the scale (twenty four inches to one inch,) 

 from which they are laid down, is so small, that the representation 

 probably falls short of the truth ; since no attempt has been made 

 to show the claws, which do sometimes appear. Yet in general, 

 where the rock has been for some time exposed, these and other 

 more delicate parts of the impression are obliterated ; and it is only 

 by cleaving down insulated specimens that I have discovered them. 



* Also the Bantam domestic fowl. — Ed. 



