The Bulkley and Babine Mountains of British Columbia are made up of a number of individual mountains and groups of mountains separated by low areas. Stocks and abundant dikes and related mineral deposits commonly occur in the high areas. In many of the low areas there are Lower Cretaceous sediments with a basin structure corresponding somewhat to the topography. Locally these sediments extend up the mountain slopes, where they are much more indurated. It is believed that the mountains are due to the presence of the intrusive bodies and to related induration and doming of the rocks in their vicinity, and that the intrusive bodies are of Tertiary age.