Channel, The English (Fr. La Manche, 'sleeve;' Roman Mare Britannicum), is the narrow sea between England and France. On the east, it joins the North Sea at the Strait of Dover, 21 miles wide, from which it runs west-south-west for 280 miles, and joins the Atlantic Ocean at the Chops, with a breadth of 100 miles between the Scilly Isles and Ushant Isle. With an average breadth of 70 miles, it is 90 miles wide from Brighton to Havre; 60 miles from Portland Bill to Cape La Hague; 140 miles - its greatest breadth - from Sidmouth to St Malo; and 100 to 110 miles west of the latter line. It occupies 23,900 square geographical miles, and contains the Channel Isles, Ushant Isle, and Isle of Wight. It is shallowest at the Strait of Dover, where a chalk ridge at the depth of twelve to thirty fathoms joins England and France. West of this, the average depth of the central portion is thirty fathoms, with hollows from forty to sixty-two fathoms deep. The English coast-line of the Channel is 390 miles long, and the French coast-line is 570 miles long. The proposed Channel Tunnel, 23 miles long, from Dover to Calais, was discussed first in 1867.