Echo sounding lines run by hydrographic agencies indicate that the floor of the Pacific Ocean between the Hawaiian Islands and the northwestern portion of North America has numerous submarine mountains or ranges which rise several thousand feet. Of particular interest are the groups of mountains recently discovered in the Gulf of Alaska which in some instances rise over 12,000 feet. From the standpoint of the physiographer problems of origin, shape, history, age, and relation to the Cordilleran border system on the American continent will be important. The seismologist has at hand definite, sizable features which may account for the presence of great earthquake tremors occurring in an area formerly believed to be practically devoid of relief. In addition these mountains form definite obstructions by which the oceanographer may partially account for the unusual currents encountered in this region with their corresponding effect on variation of temperatures and correlation with . . .