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 laminae 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 considered 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 

 comparatively but a few years have elapsed since attention has been call- 

 ed to them. 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- 

 stone, having made out four species of animals, some of which are conjec- 

 tured to belong to gigantic Batrachians. Near Dumfries, the foot-marks 



