EARLY CAMBRIAN STRATIGRAPHY. 
107 
which “may include some beds newer than the Cambrian but 
not distinctly separable from it.” 1 
This conception of the stratigraphy and of the relations 
between this section and that along the main line of the Canadian 
Pacific railway to the south has been confirmed by the recent 
discovery 2 of Lower Cambrian fossils in the upper beds of the 
Bow River series and of drift blocks indicating the Ordovician 
age of the upper portion of the Robson massif, all of which was 
mapped by McEvoy as Castle mountain. 
The Cambrian strata are divided by Walcott 2 into nine forma- 
tions, see page 109, but fossil collections were only secured 
from general horizons in the Hota, Chetang, and Titkana. Mc- 
Evoy’s Bow River series is divided into a Cambrian and Pre- 
Cambrian sequence, but the thickness of the basal Cambrian 
sandstones (McNaugliton) is described 3 as very uncertain since 
it is difficult to determine the line of demarcation between 
them and the unconformably underlying Miette sandstones. 
Here the lack of knowledge concerning the relations between 
the two basal sandstone series leaves some doubt as to the 
Pre-Cambrian age of the Miette, but the Lower Cambrian age 
of at least a portion of the basal elastics is certain. In this region 
the Albertella fauna is assigned 4 to a position 350 feet below 
the top of the 900 feet of Chetang limestones, all of which 
is placed above the Lower-Middle Cambrian boundary. While 
the Albertella fauna is thus separated by a considerable interval 
from w T hat seems to be the correct position for the top of the 
Lower Cambrian, the actual data with regard to the distribution 
of the Olenellus fauna in the Hota formation below that boundary 
are very meagre. 4 On the line of section fragments assigned 
to the genus occur in the upper layers of this formation on 
Mahto mountain, a recognized species ( Olenellus canadensis ) 
was obtained from a horizon placed about 300 feet below the 
top and an undetermined species near the top of the formation, 
and the new subfauna with Callavia, Wanneria, Holmia ?, and 
Olenellus 6 is assigned to the 800 feet of which this formation 
1 Ann. Rept. Geol. Survey, Canada, for 1898, Vol. XI, 1901, Part D, geological 
notes on map. 
2 Walcott: Smithsonian Misc. Coll., vol. 57, No. 12, 1913, pp. 327-343. 
8 Idem, p. 339. 
4 Idem, p. 338. 
* Idem, vol. 57, No. 11, 1912, pp. 309-326. 
