392 L. D.' Barling — Protichnites and ClimacticJinites. 



tioDS of Kishinouje'" indicate that the apex of the Y-shaped 

 impressions in the somewhat similar track of Zimulus -points 

 forward. As ah-eadj mentioned, however, Packard records'^ 

 the fact that the oblique furrows of Limuhos are directed in 

 a direction reverse to that of the ridges of Climactichnites, 

 and Patten," in comparing the tracks with those of Limulus^ 

 states that the tracks showed a beginning in a hollow in the 

 sand, and thus corresponded to those of Limulus "which 

 remains buried on recession of the tide and upon its first return 

 crawls and then swims away." 



Grabau"" mentions GlimaGticlinites-Y^^ trails in the Silurian, 

 which may have been produced by eurypterids with bilobed 

 telsons, myriopodus types, or insecta. 



Climactichnites may be characterized as consisting of a series 

 of more or less transverse subparallel ridges bounded on either 

 side by a lateral ridge. They have been found on Upper 

 Cambrian sandstones in Ontario, New York, and Wisconsin. 

 Let us examine the trails critically to see whether or not they 

 speak for themselves, dividing fact from inference as we did 

 in discussing Protichnites. 



Facts: {a) the lateral ridges may be almost absent or may 

 be very coarse, in w^hich case they are regularly swollen at 

 intervals equal to the distance between the transverse ridges, 

 and each swollen portion appears to merge at one end into an 

 adjacent cross ridge ; {h) the lateral ridges vary from IJ to 4-i 

 inches apart in specimens from Wisconsin, but average 4 to 6 

 inches apart in specimens from New York and Canada ; {c) the 

 transverse ridges are usually arched or Y-shaped but they are 

 frequently very irregular, even sinuous or double bow-shaped, 

 and the angle of the Y varies within wide limits ; the apex of 

 the Y is not always symmetrically spaced, betraying a general 

 tendency to swerve to the outside on curves, but being irregu- 

 larly disposed even on tangents ; {d) there is more or less inter- 

 ruption of each ridge at the apex of the Y, so much so that the 

 line connecting the apices sometimes forms a slightly marked 

 ridge; {e) the transverse ridges are usually equally spaced, but 

 this again varies greatly and the ridges may be small and 

 irregularly spaced ; {f) lying upon the ridged trail in the speci- 

 men from New Lisbon, Wisconsin (see tig. 2), is a series of 

 very closely spaced almost semicii'cular raised lines which cross 

 the transverse ridges without interruption or deflection ; (g) the 

 convexity of the lines mentioned m f is directed in the same 

 direction as the apex of the Y-shaped arch in the transverse 

 ridges; (A) Todd^^ mentions longitudinal lines which are some- 

 times wavy ; {i) the trail completely reverses its direction in a 

 distance almost equal to 5 times its width, the sharpest curve 

 observed being one with a radius of little more than one-half 



