JJ.—DEscrIPpTION OF TRACKS FROM THE FINE-GRAINED SILICEOUS 
MUDSTONES OF THE KNOYDART FORMATION ( E0-DEVONIAN) 
oF ANTIGONISH County, Nova Scotra..—By H. M. Amr, 
M. A., D. Se., F. G. 8S, of the Geological Survey of 
Canada. 
(Read May 13th, 1901.) 
ICHTHYOIDICHNITES ACADIENSIS, n. sp. 
Plate no. 2. 
1897, Protichnites carbonarius, Fletcher, (partim) Annual Report, Geol. Survey 
of Canada, new series Vol. 2, p. 68 P. 
These tracks are arranged in pairs and indicate an animal 
possessing bilateral symmetry with powers of locomotion and 
suspension in water without leaving a trail or mark of the body 
proper. They were evidently made by some fin or spine-like 
appendage attached to the body of the organism, which may 
have been that of an acanthodian or other early form of fish 
existing in the early Devonian lake, sea or estuaries of Nova 
Scotia. 
There are eight pairs of tracks preserved on one slab showing 
seven completed strides, steps or series of advances. They con- 
sist of two more or less parallel linear depressions, which spread 
slightly anteriorly in the direction of progress or advance for- 
ward, accompanied posteriorly by two somewhat raised ridges 
or monticules, the result of the accumulation of the once soft 
fine mud or sediment by the fine or spine-like pointed appendage 
in the forward motion of advance. As preserved, the eight 
pairs of tracks indicate that at the time they were made the 
animal took a turn to the left and changed the direction of its 
course by an angle of thirty-eight degrees. 
1 Published with the permission of the Director of the Geol. Survey of Canada. 
(330) 
