principal series of tracks, important both on 

 account of their size and their preservation. 



One of them is the series designated No. 1 in 

 Mr. Gibbes' canvas drawings and in the pub- 

 lished plans. This series is in a great measure 

 protected outside the present face of the cliff 

 by a wooden cover which is only raised when 

 visitors are examining the foot prints; but Mr. 

 Gibbes says that these tracks are certainly not 

 in as good condition now as they were before 

 the last winter. And it is reasonableto assert that 

 with every rain, with every frost, every new cast 

 made, every personal examination by inquisitive 

 and sacriligious hands, these hieroglyphics 

 must suffer in sharpness and accuracy of detail. 



The animal which made these footprints ap- 

 pears to have been moving from the cliff out- 

 ward using the term cliff for reference only 

 and since the first visit of Dr. Harkness and Mr. 

 Gibbes and Prof. Le Conte, a short drift or tun- 

 nel has been run into the cliff exposing other 

 footprints and also the footprints of a mammoth 

 intermingled. 



The indications point to the great probability 

 of the two animals being there at or very near 

 the same time, because one of the footprints of 

 the mammoth obliterates one of the footprints 

 of the preceding animal. 



And here it is proper to state that I use the 

 term mammoth provisionally. The diagram 

 designated series No. 1 continued, illustrates 

 nearly to scale this combination of footprints; 

 those only partly exposed are to be uncovered 

 in the casts. 



Upon a minute examination of some of the 

 footprints of the first animal or the so-called man, 

 and the material in which these prints were made, 

 a very striking fact was demonstrable. 



A lower stratum of mud had been formed, had 

 dried considerably, and the surface was seem- 

 ingly quite firm, suffering very little impres- 

 sion to be made in it. Above this had been de- 

 posited another layer of mud about three-fourths 

 of an inch thick and apparently quite soft. 

 There is no doubt on this point of the two layers, 

 because the upper layer of three-fourths inch is 

 in parts removed and is removable, and is in 

 places lying ready to be swept away, so that 

 there is no assumption of the existence of these 

 two layers. The existence, consistency, and re- 

 lation of these two layers is very important in a 

 study of the footprints. The foot of the animal 

 in its deliberate walk, and with its great weight, 

 would very easily press from under it all, or 

 nearly all, of the material of the softer upper 

 layer, especially if the lower layer were unyield- 

 ing or nearly so. And if this upper soft layer 

 were not yet "set" it is very likely that part of 

 the material would settle back when the foot 

 was removed. Moreover, if the lower layer 

 were in that stiff, yet sticky condition which 

 most of us have experienced in walking, riding 

 or driving through adobe soils, there would be 

 occasional lifting up of some parts of that layer 

 by its sticking to the sole of the foot. 



Now, upon careful examination, this result 

 is clearly exhibited in several of these foot- 



prints; the foot pressed the softer material of 

 the upper layer from under it and rested on the 

 stiffer layer beneath it, and when the animal 

 raised its foot the softer material, though quite 

 soft, was not thii) enough to flow back into the 

 print, so that a fair marginal edge may, in 

 some instances, be traced. Again, when that 

 foot was raised, or when the second foot was 

 raised from the same track, it lifted with it an 

 irregular area of unequal thickness from the 

 more tenacious layer beneath. In some places 

 this removed area goes out to the border of the 

 imprint, and in no two instances is it identical 

 in shape or location. Where the surface of the 

 lower stratum is not wholly removed by such 

 adhesion of the stiffer mud to the sole of the 

 foot, there is, in some cases, a narrow border a 

 few inches long and an inch or more in breadth 

 of it smoothed apparently by the slightly for- 

 ward or backward slip of the foot when lifted, 

 just as would happen to-day to an animal walk- 

 ing over a stiff adobe soil. The soft unctuous 

 character of the upper stratum naturally aided 

 this slipping movement, no matter how little 

 it may have been. 



it is these pieces of smoothed, narrow border 

 which have been aggregated to form the san- 

 daled foot of a so-called man. But I arn con- 

 vinced that a study of the facts which are now 

 presented, and the whole appearance of the 

 surface roughened by the lifting of part of the 

 lower stratum, lead to the conclusion that no 

 sandaled foot was necessary to produce the im- 

 pression indicated. Other facts to be men- 

 tioned will sustain this deduction. 



Two or more foot prints exhibit other in- 

 teresting minutiae of detail. At what may be 

 supposed the heel of the animal's foot, the in- 

 ner sloping of the soft marginal mud shows 

 distinctly a series of lines as if made by a mass 

 of hair or other similar material attached to 

 the foot; and at what may be supposed may be 

 the toe end of the animal's foot, the inner slop- 

 ing of the same layer of softer mud indicates 

 that when the foot was lifted the forward part 

 had a slight movement inward. 



I examined these markings carefully to see if, 

 by any possibility, minute remains of hair or 

 other material might be still attached to the 

 mud. And where so much of interest is cen- 

 tered it seemed exceedingly important that a 

 member of the academy should be present 

 whenever any new drifts are to be made be- 

 cause the minutest details should be gathered. 

 This was carried out at the opening of the last 

 two mammoth tracks, when Dr. Harkness and 

 Prof. Joseph Le Conte and Mr. Gibbes were 

 present. 



In this series of tracks it may be safely as- 

 serted that there are no two which are exactly 

 alike in outline or imprint, whatever significance 

 may be attached to that fact. 



In the line of these tracks, or at least in the 

 pathway of 20 of them, reckoning from the 

 half-exposed one in the drift, there are no other 

 tracks except the three or four mammoth tracks 

 at the drift, or tunnel under the cliff, and som e 



