During a detailed geological survey of the North Thompson Valley map area2 in south-central British Columbia, carried out for the Geological Survey of Canada during the summer of 1921, the writer was fortunate enough to encounter certain highly fossiliferous members of the early Tertiary coal-bearing beds which lie at the bottom of the North Thompson River trench from 40 to 55 miles north of the city of Kam-loops. In the hope that the topographical location, structure, and age of the beds might reveal some precise information concerning the character and date of the Laramide revolution and Tertiary faulting in the southern interior, special importance was attached to their study, and fairly complete collections of fossil plant remains were obtained.
The upland surface into which the North Thompson River has cut a valley about 3,000 feet deep is, at least locally, a peneplain. The age . . .