] 64 FISHHSTG-GEOUNDS OF NORTH AMBEICA. 



range from 50 to 95 fathoms ; the depths of water whore the observations were tal<ea were 2 to 10 fathoms; the records 

 are about as imperfect at this station as at Boon Island. 



Petit Minan light-house.— Patit Manau Island consists of a group of low, rocky islets, situated about 2 miles from 

 land, off the western entrance to Pigeon Hill Bay, and 27 miles from Mount Desert Eock. They are surrounded by 

 deep water, the observations having been taken where the depths range from 8 to In fathoms. 



KELATIYB POSITIONS OF THE STATIONS. 



The three most southern of the temperature stations, those at the Tortugas, Oarysfort Eeef, 

 and Fowey Eocks, are located on the northern and western edge of a deep and comparatively 

 narrow channel, called the Straits of Florida, which extends first easterly from the Gulf of Mexico 

 and then northerly into the Atlantic Ocean. This channel, which is occupied for its entire width 

 and length by the Gulf Stream, is bounded on the north and west by Florida, on the south by 

 Cuba, and on the east by the Bahama banks and islands. Its length is about 350 miles, but the 

 temperature stations are limited to its central aud western portions, all being situated on the 

 Florida Eeefs. In front of the Tortugas, the 100-fathom curve is distant about 15 miles from the 

 southern edge of the reefs, which are located at the southern end of the submerged continental 

 slope borderi;ig the west coast of Florida for a width of 110 to 145 miles. At Oarysfort Eeef, the 

 100-fathom curve is distant only about 7 miles from shore, and at Fowey Eocks only. 2 J. miles. 

 The deepest water in the straits occurs at the western entrance, opposite the Tortugas, and in 

 places exceeds 1,000 fathoms, the southern and eastern sides of the straits being generally deeper 

 than the northern and western. The influence of the great body of warm water composing the 

 Gulf Stream is felt directly upon the Florida Eeefs, although these reefs are known to be bathed 

 by a narrow counter current flowing to the westward. The axis or warmest band of the Gulf 

 Stream passes nearer the southern and eastern than the Florida side of the channel. 



The Tortugas Eeefs are situated at the western end of the Straits of Florida, on the northern 

 side, where the distance across from land to land is about 90 miles. The Tortugas station, how- 

 ever, is in a somewhat protected position, and local influences are perceptible in the temperature 

 records. At Fowey Eocks, the width of the chann,el is reduced to about 40 miles, this width 

 being the least of any in the straits. The stations at Oarysfort Eeef and Fowey Eocks both 

 occupy more exposed positions than the one at the Tortugas, and are therefore better located for 

 asQertaining the temperature of the open waters bordering the reefs. 



Between the Florida Eeefs and the first station to the north (Martin's Industry light-ship, 

 South Carolina), a distance of about 6J degrees of latitude intervenes. Within this distance the 

 100-fathom curve and the inner edge of the Gulf Stream gradually recede from the coast line as 

 far as Georgia, whence to near Cape Lookout, Iforth Carolina, they retain a nearly uniform dis- 

 tance from the shore. Along this section of the coast the submerged continental plateau has an 

 average width of about 55 miles to the 100-fathom curve, which lies just within the inner edge of 

 the Gulf Stream or " Cold Wall." The bottom slopes gradually from the shore into depths of 

 about 50 fathoms, beyond which the descent is very rapid. Just south of Cape Lookout the 100- 

 fathom curve bends in somewhat toward the shore, and in front of Cape Hatteras the submerged 

 continental border is only about one-third as wide as it is farther south, the Gulf Stream also 

 approaching nearer to the land. IsTorth of Cape Hatteras the 100-fathom curve again recedes 

 from the shore and the Gulf Stream is deflected toward the east. 



Between Georgia and Cape Hatteras there are four stations, of which three are light-ships, 

 located several miles off shore, in depths of 5 to 11 fathoms. Martin's Industry light-ship is ofl:' 

 the entrance to Port Eoyal Sound, South Carolina, in front of Martin's Industry Shoal, which 

 separates the south and southeast channels; Eattlegoake Shoal light-ship is just north of the 



