KANSJiS ACADEMY OF SCIENCE. 



elevated hind toe just reaching the ground at its extremity, as in the modern snipes 

 and other wading-birds, or in the family of sea-gulls and terns. That the track is 

 probably that of a right foot rather than a left, is indicated by the wider separation 

 of the outer toe from the middle toe, resulting from the greater versatility of the 

 outer toe as compared with the inner toe — a character illustrated in many families 

 of existing birds, and carried to an extreme in the cuckoos and the woodpeckers, in 

 which the outer anterior toe is entirely reversed in its direction and becomes a 

 backward-pointing member. 



It will be seen from the accompanying cut that our bird-track exhibits the 

 imprint of all four of the toes. The outer anterior toe is represented for fully 

 two-thirds of its length. The middle and inner anterior toes are entirely im- 

 pressed, even to the claws at their extremities — the claw being very distinctly 

 marked upon the middle toe. The ball of the foot has left a deep impression, and 

 the posterior toe has made an unmistakable imprint upon the sand similar to those 

 made at the present time by birds whose hind toes just reach the ground. That 

 this impression is avian in its character rather than reptilian, is evident from the 

 imprint of the hind toe, for no dinosaur or other reptile, either recent or extinct, 

 is known to have a backwardly directed toe. Some dinosaurs have a fourth small 

 or rudimentary anterior toe, but in no case has a posterior toe been discovered. 

 The absence of the impression of a posterior toe in the so-called bird-tracks of the 

 Connecticut river Triassic sandstone has led the best authorities to consider those 

 tracks reptilian rather than avian. The small size of our Dakota track is a con- 

 firmatory indication of its avian character. It measures only two inches from 

 anterior middle claw to claw of posterior toe, being a little larger than the foot of 

 Professor 0. C. Marsh's Ichthyornifi victor as restored by him in his famous monograph 

 of the Odontornithes. The restoration of the foot of Ichthi/ornis, however, was based 

 upon a single phalangal bone, the only portion of the foot yet found, the rest of 

 the skeleton of the foot having been restored in exact imitation of a living species 

 of tern, which among recent birds Ichthyornis seems most closely to resemble. 



The discovery of this avian footprint in the Dakota rocks considerably lowers 

 the geological horizon of Kansas birds. The Niobrara group of the Cretaceous has 

 hitherto furnished all our knowledge of ancient bird-life in Kansas. From these 



