1852.] OWEN— POTSDAM SANDSTONE FOOT-TRACKS. 219 



impression is much shallower and fainter than in the foregoing foot- 

 prints, but it still shows the alternate deep and shallow parts. Al- 

 though the impressions are less regular than in the before-described 

 series, and the small innermost ones are less recognizable, yet they 

 are discernible in certain parts, as at c, c, and they, in like manner, 

 mark the boundaries of three sets of impressions on each side of the 

 median one. 



The first set consists of a pair, «', «", of nearly equal impressions, 

 with occasional indications of a third print forming an inequilateral 

 triangle. The second set of impressions is a transverse, more widely 

 parted, pair, h, h\ the innermost being the smallest, the outermost 

 the largest and sometimes, as in 1 X, divided uito two, which are, 

 however, included in a common circumference. Then that impres- 

 sion, c', c", which has been described as the outermost of the pair to 

 which the small innermost impression, c, belongs, is very large and 

 more distinctly bilobed than the outermost of the preceding pair, 

 and its long axis is turned at right angles to that of the preceding 

 outermost impression. The longitudinal extent of the three sets of 

 impressions on one side is 5 inches. The transverse interspace be- 

 tween the two small innermost impressions, c, c, is 2 inches 2 lines, 

 between the outermost, «", «", of the three sets of impressions from 

 their outer borders 7 inches. The general resemblance of these suc- 

 cessive series of three sets of impressions with those of the better- 

 defined tracks before described leave no doubt of their having been 

 made by the same genus of animal, but it would seem to be by a 

 different species having a body broader in proportion to its length. 



The sandstone allows a character of the lateral impressions to be 

 seen which was not so distinctly recognizable in the casts, namely the 

 great depth and ^gular figure of the bottom of the impressions, with 

 some irregular angular notches towards its circumference, indicating 

 them to have been made by a limb shod with a hard substance ter- 

 minating in a somewhat obtuse point with angular processes from its 

 base. This character of the impressions is irreconcileable with their 

 having been formed by the convex sole of the foot of a Chelonian 

 or by the more flattened foot of a Batrachian or Saurian reptile, or 

 by the hoofed or padded foot of any mammal. 



4. Protichnites multinotatus. PI. XII. (|- nat. size.) 



Casts of impressions along an extent of 4^ feet, forming part of a 

 series which was traced for an extent of 10 feet uninterruptedly, ex- 

 hibit a strong deviation of the intermediate continuous groove from 

 the mid-line between the two lateral series of impressions. The 

 breadth of this track from the outer border of the outer impressions 

 nowhere exceeds 3|- inches. The impressions are subcircular with 

 smooth, rounded, ill-defined borders, of varying depth, but most of 

 them faint and shallow. Commencing at the end of the series, where 

 they are least distinct, the intermediate groove inclines to the left and 

 soon gets upon the innermost of the impressions along the left side. 

 At about halfway from the other end it becomes deeper, obliterates 

 many of the prints on that side, and has been impressed so strongly 

 as to force up a ridge of the sand upon its left side. Some faint 



