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242 Canadian Record of Science. 
LAKE St. Joun BAsIn. 
From the Lake St. John and Upper Saguenay district the 
explorations of Sir Wm. Logan, James Richardson, Scott 
Barlow, Dr. Selwyn, Prof. Laflamme, Mr. F. D. Adams, Mr. 
D. N. Saint Cyr and others have afforded a considerable 
quantity of material wherewith to ascertain by means of 
the fossils to what age or precise geological horizon the dif- 
ferent strata there met with belonged. As early as 1829, in 
a report by Captain F. H. Baddeley, addressed to the Legis- 
lature of Quebec, the black bituminous schists of the Utica 
were recorded in this Lake St. John or Upper Saguenay 
district. From the collections made by Mr. Richardson, 
Billings described the Triarthrus glaber of Lake St. John as 
a new and undescribed form. ‘This trilobite is the largest 
one of the genus yet known, and the specimens obtained by 
Mr. Adams in 1883 and 1884 show that its dimensions vary 
greatly, and even surpass those mentioned in the type 
specimens. 
From the “‘ Mouth of the Ouatchouan River,” Lake St. - 
John, Mr. Adams obtained the following species in a rusty 
weathering somewhat indurated black bituminous shale :— 
1. Orthograptus quadrimucronatus, Hall. 
2. Leptobolus insignis, Hall. 
3. Endoceras proteiforme, Hall. 
4. Triarthrus glaber, Billings. 
Amongst the specimens of 7. glaber, collected by Mr. 
Adams, we find that the occipital or neck segment is fur- 
nished with a small somewhat depressed linear tubercle 
about the centre, a character which had not heretofore been 
noted in this species. The fact that it is destitute of genal 
spines, of spines along the median axis of the body or 
attached to the occipital segment as in T. spinosus, and that 
the body segments of this species (‘T. glaber) are destitute 
of the tubercules along the median axis of the body, is quite 
sufficient warrant to retain the designation glaber for this 
Lake St. John species, although it does possess one occipital 
tubercle as single ornamentation visible. 
