73 
Description, The track is deeply impressed, very large, and almost 
as broad as long; the toes are very broad, extend only a short distance 
beyond the web or pad, and terminate in pointed hoofs; there is no sign of 
a fourth toe; the distal half of digit III is at a higher level than the side 
toes and the sole of the foot; the heel is short, moderately narrow, and 
well impressed. 
Figure 8. Amblydactylus gethingi; type, Cat. No. 8555, Geol. Surv., Canada; one-twelfth 
natural size. 
There is no evidence of separate phalangial pads. Digit II is not 
cut away from the metatarsal or heel pad. Posterior to the depression of 
the heel the rock slopes upward and backward. This may represent the 
impression of part of the posterior edge of the metatarsals, which were not 
carried perpendicular above the phalangies. 
Greatest length of track, from posterior edge of heel to tip of digit III, 
640 mm.; greatest breadth, 590 mm.; from centre of heel to tip of digit 
II, 560 mm.; to tip of digit IV, 535 mm. Divarication of digits II and 
III, 32 degrees, of III and IV, 24 degrees. 
Family, Tetrapodosauridae new family 
Family Characters. Habitually quadrupedal; medium sized; bluntly 
pointed hoofs; trackway wide; stride short; no caudal impression. 
Tracks of this family were doubtlessly made by quadrupedal, pre- 
dentate dinosaurs. 
Genus, Tetrafodosaurtjs new genus 
Genotype, Tetrapodosaurus borealis new species 
Generic Characters. Quadrupedal; toes enclosed in pad or web; 
manus impressions in front of and completely separated from those of the 
pes; manus short and broad, five toes, digitigrade; pes of medium length, 
semiplantigrade, with four toes. 
Tracks of this genus were observed at only one horizon. They may 
well have been made by an ancestor of one of the Upper Cretaceous Cera- 
topsia. 
35923—5 
