520 BULLETIN OF THE BUKEAU OF FISHEEIES 



and are inclosed by rims so much shallower that they have been made the field of con- 

 siderable hydrographic investigation. These, for want of better names, I may 

 christen (1) the Cape Ann sink, lying near Stellwagen Bank, centering about 12 miles 

 southeast of Cape Ann, having a general depth of 50 to 70 fathoms (91 to 128 meters) 

 and a greatest depth of 99 fathoms (181 meters), and inclosed by a continuous rim 

 of 40 fathoms (70 to 75 meters) or shallower; (2) the Isles of Shoals sink, centering 

 28 miles northeast of Cape Ann, having a general depth of 80 to 100 fathoms (146 

 to 183 meters), and inclosed on the south and east by the shallows of Jeffreys Ledge 

 and on the north by depths of 60 to 70 fathoms (110 to 128 meters). The Fundy 

 deep, south of Grand Manan Island at the mouth of the Bay of Fundy, is a basin 

 some 27 miles long, with 100 to 112 fathoms (183 to 205 meters) and its deepest 

 spot 165 fathoms (302 meters). 



The two arms of the deep trough or basin of the gulf are separated by a roughly 

 triangular area, with depths ranging generally from 70 to 90 fathoms (128 to 165 

 meters) but rising at its apex (roughly, in the center of the guK) to within 4J^ fathoms 

 (8 meters) of the surface, as the dangerous, rocky shoal known as Cashes Ledge, the 

 patch less than 30 fathoms (55 meters) deep being about 6 miles long in a southwest- 

 northeast direction. Other offshore shoals in the gulf proper, which deserve mention 

 here because I shall have occasion to refer to them later as landmarks, are as follows : 



1. Stellwagen Bank, lying between Cape Cod and Cape Ann at the entrance to 

 Massachusetts Bay, 9 to 20 fathoms (16 to 37 meters), with deeper channels north 

 and south of it. 



2. Jeffreys Ledge, a narrow ridge extending northeasterly from Cape Ann for 

 about 45 miles, with depths less than 50 fathoms (91 meters), shoalest place 18 

 fathoms (33 meters). 



3. Platts Bank, situated about 34 miles east-southeast from Cape Elizabeth, 

 which rises to within 29 fathoms (53 meters) of the surface. 



4. Jeffrey Bank, off Penobscot Bay, some 26 miles south of the outermost islet 

 (Matinicus Rock) , where there is a small area within the 50-f athom curve with a 

 shallowest depth of 46 fathoms (84 meters). 



5. Grand Manan Bank, a small shoal about 7 miles long lying about 18 miles 

 south of Grand Manan Island; general depth 30 to 40 fathoms (55 to 73 meters). 



6. Lurcher Shoal, a patch of broken, rocky bottom 1.5 to 20 fathoms (3 to 37 

 meters) deep, 15 miles off Yarmouth, Nova Scotia. 



7. German Bank, a considerable but vaguely defined area west of Cape Sable, 

 with depths of 30 to 35 fathoms (55 to 64 meters) bounding the debouchment of the 

 Northern Channel into the basin of the gulf. 



Mitchell (1881) has calculated that the mean depth of the gulf north of the sill, 

 including its navigable bays and tributaries, is about 75 fathoms (137 meters). 



The banks that form the southern sill of the gulf have been described frequently, 

 and because of their importance in navigation their main features are summarized in 

 the coast pilots issued by the British and United States Governments. The di- 

 mensions and area of Georges Bank, one of the most famous and productive fishing 

 grounds in the North Atlantic, are mentioned above (p. 518). On the southern and 

 eastern parts the depths range, in round numbers, from 30 to 40 fathoms (55 to 

 73 meters). Over its northwestern one-third the water is shallower, with a consider- 



