Mesozoic and Cenozoic Geology and Paleontology. 119 
ding through them, or exposed in the river valleys where they have 
been cut away, extend from the lower portion of the Chilcotin river 
westward to that part of the Chilanco due south of Puntz lake; on the 
Chilco, to a point a few miles west of the 104th meridian, and on the 
Chilcotin itself, may stretch to Chizicut lake, and thence extend north - 
eastward, their boundary nearly following the Clusco river for some 
distance. They characterize the greater part of the Nazco valley, and 
the plateau extending east and west from.it, and probably reach the 
western slope of the range of hills crossing the Blackwater at the upper 
canon. The rocks exhibited in these flows are usually true basalts or 
dolerites of various textures, and from iron-gray to dark greenish 
and nearly black colors, and often contain much olivine. The vesicles | 
are comparatively seldom filled with infiltrated minerals, though near 
the sources of the Nazco they are almost invariably so, the material 
being pale chalcedony, passing over in some instances to chrysopraze. 
In this vicinity, and near Cinderella mountain, some beds are wacke- 
like and scoriaceous; and the soil of the water-shed region between the 
Nazco and Bae-zae-coh, on the Cluscus trail, seems to be almost entire- 
ly composed of fine rusty pumiceus fragments. 
Samuel H. Scudder described, from. a very fine grayish and greenish- 
white fire-clay, in thin layers, with coniferous and angiospermous 
leaves and seeds, 84 inches thick, which is superimposed upon a two- 
inch layer of carbonaceous clay, or impure lignite or matted leaves, 
mingled with clay, and succeeded by 36 feet of sands and clays, 
at Quesnel, the following insect remains, to-wit: Formica arcana, 
Hypoclinia obliterata, Aphenogaster longeva, Pimpla decessa, P. 
saxea, P. senecta, Calyptites antediluvianum, Boletina sepulta, 
Brachypeza abita, B. procera, Trichonta dawsoni, Anthomyia inani- 
mata, A. buryesst, Heteromyza senilis, Scitomyza revelata, Lithortalis 
picta, Lonchea senescens, Palloptera morticina, Prometopra depilis 
and Lachnus petrorum. 
Robert Bell, in his report on an exploration between James bay and 
lakes Superior and Huron, says, that in the region about the height 
of land, at the head of the east branch of the Montreal river, the lower 
levels are filled with great mounds and steep ridges of gravel and 
cobble-stones. The valley of this river, for some miles before it joins 
the main stream, is also covered with similar materials. The first 
limestone pebbles were observed on the Mattagami, 24 miles below 
Kenogamisse Lake. Along the Missinibi river, for many miles above 
its junction with the Mattagami, a blue clay, only occasionally holding 
