? 
166 Association of American Geologists. 
The first and most obvious impression upon the mind, on looking at the 
indentations or marks, is their thin tripartite form, resembling the tread 
or foot-mark of those kinds of birds which show three toes, the fourth one 
being rudimental, and are referable to no other known kind of animal. 
The tracks or foot-marks in several localities are arranged in a determin- 
ate order, like those of a bird or fowl moving in a straight line, the toes 
or marks in all such cases being alternate; that is, if the right foot be 
presented on the rock, the left would next follow, and thus right and left 
in regular succession, sometimes with many repetitions. In other instan- 
ces, the foot-marks presented no determinate direction or order, as might 
naturally be supposed of a bird or any other animal having no particular 
place or object in view. 
In all cases where a succession of tracks was observed, there was an 
uniform correspondence as to size, and considerable regularity as to dis- 
tance between the tracks. Whatever deviations were observed, they were 
not greater than might be supposed to take place in animals possessed of 
voluntary motion. 
On some surfaces, not unfrequently one or more different kinds of track 
were exposed, belonging, as was reasonably conjectured, to different spe- 
cies and genera of ornithichnites. 
That the slaty material of the rock showed that the impressing body 
possessed force or weight, for frequently the thin layers or lamine were 
bent downwards for an inch or more, and that the mud of which the slate 
was formed was of a highly adhesive or tenacious character. 
In all cases the foot-marks or part impressed, was the fixed part of the 
rock ; the part removed when the lower side was turned upwards, shewed 
the cast or what corresponded with the toes or foot. That no trace of 
any organic matter could be perceived occupying the cavity or mould, the 
cast or part in relief being in all respects like the material of the rock of 
which it formed a part. 
Finally, that the foot-marks belonged to a group of rocks which must 
be idered to have been produced by the same general causes which 
gave rise to the new red sandstone of Europe, and referable only to that 
sandstone. This sandstone presents foot-marks in many localties, though 
_ Comparative] y but a few years have elapsed since attention has been call- 
ed to th Some of the specimens have reached this country, and had 
they not, the information is well given by Dr. Buckland in his Bridgewa- 
ter Treatise. The most remarkable of these foot-marks, is that of the 
chirotherium from the quarries of Hesberg, near Hildburghausen in Sax- 
ony, and greatly resembles a fleshy human hand. These, in the drawing 
and in the specimen which we have seen, are alternately right and left. 
Other foot-marks have been observed by Mr. Linse in the same sand- 
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