67 
digital impressions to near their distal ends taper very gradually, beyond 
this they narrow abruptly and terminate in long, vertical slits, which must 
have been made by long, narrow claws. 
The total length of the track, measured from the posterior edge of the 
centre of the heel to the tip of the central toe, is 125 mm.; greatest breadth, 
across digits II and IV, 125 mm.; centre of heel to tip of digit II, 95 mm.; 
same point to tip of digit IV, 100 mm. Divarication of digits II and III, 
38 degrees; of III and IV, 39 degrees. 
Figure 4. Columbosauripus ungulatus; type, Cat. No. 8551, Geol. Surv., Canada; 
one-half natural size. 
Genus, Irenichnites new genus 
Genotype, Irenichnites gracilis new species 
Generic Characters. Functionally bipedal; tridactyle; digitigrade; 
digits well spread, not bound together by pad, and of uniform breadth 
throughout; claws blunt; digit II cut away from rest of foot; phalangial 
pads faintly shown; heel impression not complete; tracks small; stride 
relatively long; trackway narrow. 
Because of the digitigrade pose, the blunt termination, wide diver- 
gence, and uniform breadth of the digits, this genus is tentatively referred 
to the family Anomoepodidse (Lull, 1904). It is realized that the long 
stride, narrow trackway, and complete absence of the hallux are features 
of considerable importance, and in which this genus differs from Anomoepus 
and its allies. It cannot, however, be better referred to any other family 
which has yet been proposed. 
