20 W. E. Logan en an Animal Track 
have thus evidence of a Lower Silurian dry Jand and can scarcely 
suppose that it was wholly destitute of vegetation, we have not 
yet discovered any certain drifted vestige of its plants along 
many hundred miles of its coast. 
The crustacean which impressed the tracks at Beauharnois 
must have been a littoral animal, tracks of which have now been 
found in several places nearer than Beauharnois to the marginal 
limit of the sea to which it belonged. These localities are St. 
Ann, Vaudreuil, Presqu’ile, Lachute, and St. Elizabeth, and they 
were last year observed in the neighborhood of Perth. In the 
last locality they are associated with a new and remarkable de- 
scription of track, for the discovery of which we are indebted to 
my friend Dr. James Wilson of Perth, who sent me specimens 
of it in the month of November last. 
The largest of the specimens was between two and three feet 
long by a foot wide, and the track upon it so singular that I 
became desirous of obtaining a greater extent of the trail. For 
this purpose, in the beginning of December, I sent Mr. Richard- 
son to Perth, where he was guided to the quarry by Dr. Wilson, 
and shewn the bed in which the tracks occur. The quarry, of 
which the strata are nearly horizontal, isabout a mile from the 
town, and with the aid of Mr. Glyn, the proprietor, Mr. Rich- 
ardson obtained in fragments, a surface which measures about 
2. 
pure silicious character which is 
so well known to belong to the 
application of snow. This of 
course cracked and destroyed thethin bed with the impressed 
