Navigation of the Strait of Belleisle by the trans-Atlantic trades ordinarily ceases about November 25, although the average formation of local ice is some two weeks later. In the River St. Lawrence the close of navigation occurs during the last week in November. =3.= NORTH ATLANTIC LANE ROUTES—UNITED STATES In accordance with the North Atlantic Track Agreement, the Hydrographic Office advises that the North Atlantic Lane Routes, agreed to in Oct. 1924, by the principal steamship companies, shown on this chart in full black lines are effective as follows: TRACK C EASTBOUND.—Cross longitude 50° in latitude 42° from Sept. 1 to Jan. 31 inclusive. WESTBOUND.—Cross longitude 50° in latitude 43° from Sept. 1 to Jan. 31 inclusive. Vessels bound to or from United States ports calling at Halifax have the option of following either the Canadian or United States seasonal tracks to or from that port, passing 40 miles south of Sable Island westbound, and 60 miles south of Sable Island eastbound, when proceeding on U. S. tracks, or 20 miles south of Sable Island eastbound, when proceeding on Canadian tracks. Vessels bound direct to Portland (Maine) may follow the Canadian Seasonal tracks. NOTE.—The above routes are liable to alterations when, owing to abnormal ice conditions it is considered advisable by the steamship lines who are parties to the North Atlantic Track Agreement. Notice of these alterations will be published by the U. S. Hydrographic Office. =4.= U. S. STORM WARNINGS. [Illustration: N. W. Winds S. W. Winds N. E. Winds S. E. Winds “Hurricane” Warning] Flags 8 feet square. Pennants 5 feet hoist, 12 feet fly. _Storm Warning Flags._—A red flag with a black center indicates that a storm of marked violence is expected. The pennants displayed with the flags indicate the direction of the wind: Red, easterly; white, westerly. The pennant above the flag indicates that the wind is expected to blow from the northerly quadrants; below, from southerly quadrants. By night the approach of storms of marked violence is indicated by: Two red lights, one above the other, for winds beginning from the northeast; a single red light for winds beginning from the southeast; a red light above a white light for winds beginning from the southwest; and a white light above a red light for winds beginning from the northwest.