APR 20 1904 



11. Fossil Footprints of the Juka-Trias of North America. 

 By Richard Swann Lull, Ph. D. 



(Read November 4, 1903.) 



"Sans duute nous devons admirer le fait qii'une crfiature si insignifiante pent laisser des traces si claires, si iiettes et si 

 inrttlfebiles, qui existent depuis des cycles de sieoles innombrables, tandis que les efforts les plus grands de I'bomme intel- 

 Icctuel lui peuvent survivre a peine et c|ue peu de siecles aneantis.sent son nom, son langage et ses oeuvres pour toujours." — 

 (Winlfler, after Deanc.) 



Introduction. 



The study of ichnology has practically lain dormant since tlie death, in 18G4, of 

 Edward Hitchcock, the founder of the science and its greatest exponent. Since that time 

 our knowledge of early reptiles, especially the Dinosauria, has arisen and it has seemed 

 wise to undertake anew the study of footprints in the light of modern palaeontology, with 

 the view not only of gaining a greater insight into the natu.re and structure of the forms 

 which frequented the ancient mud flats and beaches of Triassic days, but also of throwing 

 light upon the correct interpretation of the remains of those evidently allied forms whose 

 bones are known. Thus, on seeing the great collection in the Hitchcock ichnological cabi- 

 net of Amherst college, Professor Osborn was at once struck with the possibilities of 

 which it gave promise and suggested to the writer the line of researcli of which this dis- 

 sertation is the first fruit. 



The writer has had full access, through tlie courtesy of the authorities of Amherst 

 college and of Dr. Edward Hitchcock, Jr., in particular, to the above named collection and 

 also to that of Mt. Holyoke college. Other lesser collections, namely, those of Rutgei-s 

 college and of Lafayette college, which contain some of the type specimens, have been 

 placed at the author's disposal, the only regret being that the magnificent gathering of 

 footprints brought together by the late Professor Marsh of Yale university is as yet inac- 

 cessible to the student. 



Free use has been made of Hitchcock's great works, the Ichnology of New England 

 ('58) and the Snpplement ('65), as well as of the numerous other papers on the subject, due 

 notice of which appears in the proper place. The drawings, with one or two exceptions, 

 have been made l)y the author directly from nature, their final preparation for publication 

 being the result of Mrs. Lull's skillful and painstaking endeavor. Special acknowledg- 

 ment is due to Dr. 0. P. Hay for his valued counsel in the solution of some vexatious 



