This part of the works is more particularly designed as an ice-breaker. The whole length of the two dikes above described, is seventeen hundred yards. The entrance to the harbor is six hundred and fifty yards in width, between the north point of the cape and the east end of the breakwater. At this opening, the harbor will be accessible during all winds coming from the sea.[28] The _Chesapeak Bay_ is a deep gulf opening from the Atlantic ocean, between capes Henry and Charles, and lying in the states of Maryland and Virginia. It is one hundred and eighty-five miles in length, extending northwardly, and its entrance is sixteen miles wide. Its general breadth varies from seven to twenty miles, and its average depth is nine fathoms; it affords a safe and easy navigation, and many fine harbors. Among these may be mentioned that of Norfolk, in the southern part of the bay near the mouth of the James. The embouchure of this river forms a spacious haven, called Hampton Roads. The channel which leads in from the capes of Virginia to _Hampton Roads_, is, at Old Point Comfort, reduced to a very narrow line. The shoal water, which, under the action of the sea, and re-acted upon by the bar, is kept in an unremitting ripple, has given the name of Rip Raps to this place. When the bar is passed, Hampton Roads afford the finest anchorage in the world, and in them all its navies might ride with perfect safety. With a view of making this a secure retreat for ships of war and for our commerce, in any future contest with a naval power, Fort Monroe was built on the point, on the right side of the channel at the entrance of the Roads; and the Castle of the Rip Raps is directly opposite the point, at the distance of about one thousand nine hundred yards. The two forts will completely command the channel, and it will be impossible for a single ship of war to pass without the permission of the power holding the fortresses. They are so constructed, as to present immense batteries of cannon upon an approaching ship, from the moment she comes in reach, from the capes, and throughout all the bendings of the channel.[29] _Chesapeak Bay_, and its tributary streams, have been known from their discovery as the great place of resort for water-fowl in the United States. This is attributed to the great abundance of their favorite food, which is found on the immense flats or shoals near the mouth of the Susquehanna, the whole length of North, East, and Elk rivers, and on the shores of the Bay as far south as York and James rivers.