[BLLs] PALAEOZOIC OUTLIERS IN THE OTTAWA RIVER BASIN 14S 



the underlying Laurcntiiin limestone and associated gneiss. These out- 

 liers are small in extent covering only a few hundred square yards. 



With the exception of a narrow fringe of fossilifei-ous strata of (Jal- 

 ciferous and Chazy age along the shore of Coulonge Lake, which is an 

 expansion of the Ottawa above the village of Fort Coulonge, and well 

 seen at Sèche Point, as well as at the point above, no other deposits of 

 sedimentary fossiliferous rocks were observed in this area. The Potsdam 

 sandstones have evidently not been deposited along these upper stretches 

 of the river basin, as the Calciferous and Chazy rest directly upon the 

 crystalline rocks. 



The largest area of the Palaeozoic strata in this direction is presumably 

 that which occupies the greater part of Allumette Island and extends 

 eastward across the channel of the Ottawa, comprising a very consider- 

 able portion of the township of Westnieath. The formations here repre- 

 sented are the Calciferous, on the west end of the island, Chazy and Black 

 Eiver, the latter of which has been particularly studied at Paquette's 

 Eapids near the junction of the south or Pembroke channel with that 

 which continues down the north side of the island. The fossils occur in 

 the usual dark-grayish limestone and are frequently silicihed, causing 

 them to stand out distinctly from the weathered or water worn surface of 

 the containing rocks. The Chazy is represented by the lower greenish- 

 gray shales and sandy beds and by the upper or limestone formations, 

 the upper beds presenting the same nodular character as seen on the 

 lower Ottawa. 



The western edge of this outlier show^s a very narroAv margin of 

 Calciferous on the shore about four miles above the town of Pembroke, 

 while the Chazy portion is represented in the town itself and for several 

 miles to the southeast. The Westmeath area, which is the eastward 

 extension of that on the island, shows but few outcrops of solid rock, the 

 country being generally Ioav and drift covered, but large masses of the 

 characteristic Chazy and Black Eiver limestone are seen at sevei'al points 

 indicating the existence of the basin over a considerable area. The 

 elevation of the Allumette Lake is about 370 feet above sea level which 

 would be about the same as for the Chaz}- and Black Eiver ridge at 

 Sand Point near Arn prior. 



Another area of considerable size, but apparently separated from 

 that just described, is seen to the south of the lower end of Muskrat Lake 

 in the townships of Statford and Bromle}'. The outlier embraces nearly 

 twenty square miles and consists of the Chazy and Black Eiver for- 

 mations only, in so far as can be determined, the latter being particularly 

 well exposed. Like other Palaeozoic outcrops in this basin, the strata lie 

 in a nearly or quite horizontal attitude, the inclinations observed being 

 only from 1° to 3°, the principal area rising in a somewhat bold escarp- 

 ment from the valley of the Muskrat Eiver to a height of seventy-five or 



