Hydrographic observations made incidental to summer patrol duties of the Royal Canadian Mounted Police vesselSt.Rocheshowed a relatively warm (6.5–8 °C.) saline (31.6‰) area in the Chukchi Sea, a cold (0.2–5.5 °C.) brackish (3–9‰) area from Point Barrow to Banks Island, and a cold (6.5–7.0 °C.) moderately saline (11.8–30.7‰) region from Banks Island through the channels to Coronation Gulf and Cambridge Bay.