ATLANTIC COAST TIDES 501 



ranges are roughly proportional to the distance from the 100- 

 fathora line. The tide reaches Hatteras about the same time as 

 the general northern coast. The range is there 3.6 feet and the 

 escarpment 30 miles away. As far south as Savannah entrance 

 distances from the 100- fathom line increase steadity, the range 

 mounts up to 7 feet, and the tide is an hour later. The line is 

 here 80 miles distant. From this point southward the line draws 

 in toward the coast, the ranges diminish, and the delay increases, 

 as the tide-impulse is now transmitted down the coast, the Ba- 

 hamas barring off the ocean to the eastward. At Canaveral con- 

 .figuration of shallows heaps up the range to 5 feet, but this is 

 local only. The coastline has analogies in the matter of long- 

 shore carriage to the middle bay. At the bay-head the greater 

 tides break the continuity of the sand bars and play in and out 

 by innumerable channels. 



THE BASIN TIDES 



Long Island sound, the Gulf of Maine, and the Gulf of St 

 Lawrence have their tides respectively 4, 3, and 2 hours after 

 the open coast tides. This delay and a simultaneity of high 

 tide for at least a part of their area constitute their common 

 tidal features. 



GULF OF MAINE TIDES 



The Gulf of Maine, according to the usage of our Coast Sur- 

 vey, includes the waters of the New England coast from Mono- 

 moy to Cape Sable, Nova.Scotia. Its basin is partially barred 

 to the south by the Nantucket and Georges shoals, to the east 

 by Browns bank. On these shoals soundings of 30 to 40 fath- 

 oms prevail. Between Browns and the Georges is a 16-mile 

 wide channel across the continental shelf, connecting the ocean 

 with the deep gulf center. Here, over an area measuring per- 

 haps a third that of the whole gulf, soundings range from 100 

 fathoms to near 200. About two-thirds the area is in more than 

 43 fathoms. The continental escarpment lies 200 miles from 

 the Maine coast, but the shelf is interrupted by the Gulf of 

 Maine and margins around it. The shoals to the east and south 

 have been well named by Mr Mitchell the Sill. To the north 

 the Bay of Fundy extends from the deep area of the Gulf to 

 Cape d'Or, Nova Scotia; to the southward lie Massachusetts 

 bay and Cape Cod bay, all on the continental shelf. 



The Maine coast opposite the deep area is deeply and minutely 



