September 19, 1884. 



SCIENCE. 



275 



track, especially in a soft, muddy surface, tends 

 to depress, and throw back the mud towards 

 the centre of the track, whereas the conditions 

 in these tracks are reversed. A longitudinal 

 vertical section of one of these tracks would be 

 nearly as in the diagram, the greatest depres- 

 sion beino' in the middle. 



___-^ 



Fig. 3. — Cross-section of impression. 



The breadth of the track-wa3 T , or straddle, is 

 the next great objection to the theory of human 

 origin. The whole breadth is from twenty- 

 eight to thirty inches, whereas man requires, 

 in walking, not over ten or twelve inches. If 

 we take the ordinary stride of a man six feet 

 high at twenty to twenty-four inches, the ratio 

 of the breadth of space required in walking 

 to this step is as ten or twelve to twenty 

 or twenty- four, or 1:2; while in the tracks 

 before us the ratio is as twenty-eight to twenty- 

 seven, the step, in fact, being less than the 

 straddle. This alone is fatal to the bipedal 

 theory, and in favor of the quadrupedal ; for 

 upon the quadrupedal theory the length of step 

 is fifty-six to sixtj'-two inches, and, the width 

 being twenty-eight to thirty, the ratio of the 

 width to the length is nearly as one to two. 



There are also evidences of a duplication of 

 tracks made by the hind-feet overstepping the 

 imprints of the fore-feet. This has been par- 

 ticularly pointed out b}~ Professor Davidson in 

 his report. 



The tracks of this series all have the appear- 

 ance of being made bj~ an animal with short 

 legs, for it is evident that there was a slid- 

 ing in and out of the foot, particularly in the 

 trough-shaped impressions of the lower horizon 

 of clay. 



When first opened, these are always filled up 

 with a compressed mass of clay and sand ; and 

 sometimes traces of a coarse, sedgy grass or 

 vegetation are found, as if it had been pressed 

 down under the foot into the clay. 



The opinion of Professor Marsh, that these 

 tracks were formed b}' one of the edentates, is 

 best in accord with the phenomena, and appears 

 the more reasonable when we give due weight 

 to the fact that some of these animals are be- 

 lieved to have walked partly upon the side of 

 the foot and leg, thus carrying their great claws 

 in such a way that they left no imprint. 



Elk (?) 



Of the supposed elk-tracks there are thirteen 

 in sequence, each track from four to five inches 



long by three and one-half wide, average step 

 eighty inches, and breadth of track thirteen 

 inches. 



Deer. 



The series referred to the deer is twelve feet 

 one inch in length, and includes ten tracks of 

 an animal with a sharp-pointed hoof, triangular 

 in form, measuring two inches by two and one- 

 half inches. 



Birds. 



The bird-tracks are numerous, and are gen- 

 erally about six inches in length and breadth, 

 showing four toes, as in the figure. 



It is well to note that the intense interest 

 attaching to the question of the human origin 

 of some of the tracks has greatly overshad- 

 owed the importance, geologically, of the whole 

 series and the lessons to be learned from them. 

 There has not been such an important dis- 

 covery of fossil tracks since the unearthing of 

 the fossil footprints in the sandstones of the 

 Connecticut valley. These last were discov- 

 ered in 1800, and served to stimulate and to 

 foreshadow our knowledge of the forms of life 

 between birds and lizards. The venerable Dr. 

 Hitchcock, the author of ' Ichnology of New 

 England,' in contemplating the evidences of the 



Fig. 4. —Bird-track. 



so-called bird-tracks of the Connecticut valley, 

 was led to exclaim, "Indeed, some of the 

 tracks of these narrow-toed bipeds have such a 

 resemblance to the feet of some lizard, that I 

 anticipate the disco veiy of front teeth." 



He cites Owen as saying, before fossil foot- 

 prints were known, that " a single foot-mark of 



