§ 15. ORNITHICHNITES, OR FOSSIL FOOT-PRINTS OF BIRDS. 557 



Virginia. The materials are red shale and argillaceous 

 sandstone, with detached beds of conglomerate.* It is on 

 the surface of the laminated argillaceous sandstones of this 

 system, and principally in the valley of the Connecticut, 

 that occur those mysterious characters, on which the 

 sagacity and unremitting labours of Professor Hitchcock, 

 have thrown so much light; but at present the nature 

 of the animals by which the foot-prints were made is in- 

 volved in obscurity, for not a vestige of the skeletons of the 

 bipeds, the lineaments of whose feet are so vividly apparent, 

 have been discovered. f 



The origin assigned to these markings was for a long 

 while disputed, but Professor Hitchcock's interpretation 

 is now generally admitted ; though the discovery of 

 bones of birds in strata of this epoch is required, before the 

 question can be regarded as determined. The num- 

 ber and variety of these footsteps are so considerable, that 

 Professor Hitchcock considers he has sufficient data to 

 warrant their arrangement in numerous genera and spe- 

 cies, belonging to several families of birds, f The abun- 

 dance of foot-prints on the Connecticut sandstones, is 

 explained by supposing the strata to have originated 

 from sediments deposited in "a tidal estuary ; and that 

 various kinds of birds frequented the low muddy shores, 

 when the tide receded, in pursuit of worms, and other 



* Professor Henry Rogers' Address at the Meeting of the Associa- 

 tion of American Geologists, May, 1844, 



f I must refer the reader to the original work of Professor Hitch- 

 cock, " A Report on the Geology of Massachusetts f to Dr. Buckland's 

 " Bridgewater Essay ;" to the " American Journal of Science," for many 

 interesting papers, by Dr. Deane, (who first drew Professor Hitchcock's 

 attention to the subject,) and other American naturalists; and to the 

 "Medals of Creation," vol.iii. p. 808. 



% See " Final Report on the Geology of Massachusetts," p. 477; and 

 the same accomplished author's admirable little volume, " Elementary 

 Geology," p. 155. 



