40 ICHNOGRAPHS OF THE 



langes usually being so much blended as to appear to be one, and its close 

 contact to the middle toe imparts to it a curvilinear form. The first and second 

 phalanges of the middle toe are much modified in form by the pressure of the 

 lateral toes. It is relatively long, massive, and fleshy. The tubercle supporting 

 the long or outer toe is large and circular, except at its junction with the first 

 phalanx of this toe; that supporting the central toe is so modified in form by 

 the compression of the first phalanges of the respective toes, as to assume a 

 rectangular form, and that supporting the inner toe does not distinctly appear, 

 as is usually the case. The claws are well marked, broad at their origin. ami 

 blunt at their termination. They are not, relatively, long, and such is the rule 

 in all the footprints ; they are remarkable for breadth and strength. 



The compactness of this footprint seems to indicate that the toes and heel 

 were confined in contact by some membranous union. The impress of that portion 

 of the central toe not joined to the lateral toes is free, and preserves the natural 

 outlines of the articulations. It will be observed that the lines of contact between 

 the heel and first phalanx of the long toe are rectilinear, as is also the junction 

 of this toe with the middle one. All the features of this fine footprint bear 

 the marks of great pressure, the oval curves of the articulations being overcome 

 by it and reduced to straight lines. The impress is not deep, yet, by the great 

 weight of the animal, it is sharply set into the stratum when it was evidently 

 in a stiffened condition. 



This variety of footprint occurs more abundantly than any other, and the 

 creature by which it was impressed appears to have flourished throughout the 

 entire period of the sandstone deposition, for its footsteps are widely distributed 

 throughout the strata. This rule applies to all the gigantic ornithoid footprints. 

 They are found at Turner's Falls at the bottom of the stratified series, and thence 

 upward through a thickness of many thousand feet. Wherever the stratified 

 rock is extensively quarried they are sure to be seen, sometimes in groups, or 

 associated with the footprints of other species. I have seen examples of the 

 strata that were impressed with as many as seventy-five distinct footprints, showing 

 series from different individuals, some larger and others smaller than in the plate. 



The stride of this powerful bird, if such it be, is about three feet, and its 

 body was consequently elevated upon long legs, as in existing struthious birds. 

 The type of the extinct birds may be assumed to be analogous to some existing 

 brevipennate tribes. It is of course impossible to fix the comparison with satis- 



