534 MANUAL OF ZOOLOGY. 



say, formed by an animal with three toes on each foot, as is 

 the case in many Waders and most Cursorial birds (fig. 233). 



Thirdly >, The impressions of the toes show the same numeri- 

 cal progression in the number of phalanges as exists in living 

 birds that is to say, the innermost of the anterior toes has 

 three phalanges, the middle one has four, and the outermost 

 toe has five phalanges. 



Taking this evidence collectively, it would have seemed, till 

 lately, tolerably certain that these impressions were formed by 

 Birds. We must not, however, lose sight of the possibility 

 that these impressions may have been formed by Reptiles 

 more bird-like in their characters than any of the living forms 

 with which we are acquainted. The recent researches of 

 Huxley, Cope, and others, go to show that the Dinosaurian 

 Reptiles possessed the power of walking temporarily or per- 

 manently on the hind-legs, and many curious affinities to the 

 true Birds have been pointed out. It is therefore by no means 

 impossible that these footprints of the Connecticut valley are 

 truly Reptilian.* 



The size and other characters of the above-mentioned 

 impressions vary much, and they have certainly been pro- 

 duced by several different animals. In the largest hitherto dis- 

 covered, each footprint is twenty-two inches long, and twelve 

 inches wide, showing that the feet were four times as large as 

 those of the African Ostrich. The animal, therefore, which 

 produced these impressions whether Avian or Reptilian 

 must have been of gigantic size. 



The first unmistakable remains of a bird have been found 

 in the Solenhofen Slates of Bavaria, of the age of the Upper 

 Oolites. A single unique specimen, consisting of bones and 

 feathers, but unfortunately without the skull, is all that has 

 hitherto been discovered ; and it has been named the ArcJm- 

 opteryx macrnra. The characters .of this singular and aberrant 

 bird, which alone constitutes the order Saururce, have been 

 already given, and need not be repeated here. 



Other doubtful remains of birds have been alleged to occur 

 in the Mesozoic series, but many of these certainly belong in 

 reality to Pterodactyles. In the Cretaceous rocks, however, of 

 the United States, occur the bones of several Wading Birds 

 (Graculavus, Hesperornis, Laornis, Telmatornis, and Pal<zo- 

 tringa). The most extraordinary of these Cretaceous birds, 



* The occurrence of many four -toed impressions in these same sandstones, 

 and the further discovery of the bones of Dinosaurian Reptiles in the same 

 beds, have rendered the Reptilian nature of many of these footprints almost 

 certain ; but some may possibly have been formed by Birds. 



