LOWER SASKATCHEWAN RIVER VALLEY. 
11 
Sponge (genus indeterminate). 
Holy sites catenularia Hall. 
Favosites niagarensis Hall. 
Cystiphyllum cf. niagarense (Hall). 
Orthis fiabellites Foerste. 
Stropheodonta acanthopteria Whiteaves. 
Leptaena cf. rhomboidalis (Wiickens) 
Leptaena sp. 
Leptaena parvula n.sp. 
Barandella ventricosa Hall. 
Camarotoechia cf. eckwanensis Whiteaves. 
Trematospira sp. 
Homeospira cf, aprinifortnis (Hall). 
Ilaenus? (fragment). 
This fauna also represents, the writer believes, a horizon of 
late Silurian age corresponding to that of the grey dolomites 
which outcrop in the jack-pine ridge, 8 miles southwest of Gyp- 
sumville and near the end of the old Gypsumville tramway near 
the shore of Lake Manitoba. The occurrence in the faunas 
of both localities of a peculiar new species, Leptaena parvula , 
which has not been seen in the lower beds of the Saskatchewan 
section, supports this opinion. These higher beds belong to the 
Leperditia hisingeri zone of the Stonewall limestone. 1 
With the exception of a small exposure of grey dolomite 
in the west bank of the river near some Indian cabins about 15 
miles above Chemahawin, the outcrops which furnished the 
fauna listed above are the last seen below Pas in ascending the 
river from Cedar lake. 
Northeast of Pas, the Hudson Bay railway traverses a 
region in which east of Reed, Clear, and Cormorant lakes, the 
Silurian dolomite generally lies at or near the surface. The 
general surface of the country east of Clear lake stands 50 feet 
or more above the lake, thus giving good drainage and freedom 
from the swampy conditions which prevail along considerable 
stretches of the road southwest of Pas. The dolomite is exposed 
at frequent intervals in cuts along the railway. The exposure 
* Geol, Surv., Can., Sum. Rept. for 1912, pp. 248-250. 
