EARLY BIRD FOOTSTEPS. 85 



lakes this conduct the more marked is, that the 

 minor facts upon which he fastens for the purpose 

 of supporting his own theory, are mostly presented 

 to us in circumstances which show their uncer- 

 tainty and the likelihood of their heing superseded. 

 For example, the earliest traces of birds do not 

 indicate marine forms, which, according to my 

 general views, ought, he says, to be the case. 

 Instead of natatorial birds, they are waders and 

 rimners. Let the reader judge of the character 

 of this objection, when he learns the real cir- 

 cumstances of the case. The traces of birds 

 here spoken of are merely a few foot-prints 

 found upon certain rock surfaces in America. 

 Not a bone of these animals has been found 

 in this early period. It must therefore be in- 

 ferred, either that the circumstances were not 

 favoura:ble for the entombment of the bodies of 

 these birds, or that our researches in the strata 

 formed at the time when they lived have been 

 insufficient to discover them. If such be the case 

 with birds which lived upon shores, — places 

 where, as we leam from the nature of the strata, 

 accumulations of sand and mud were constantly 

 taking place, — it is of course not to be expected 

 that any remains of natatorial birds should be 



