]64 FISUING GROUNDS OP NORTH AMERICA. 



likuge from 00 to 'J.') l:ulioms; the tleptlis of water where the observations were taken were i to 10 fathoms; the rceords 

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



Petit Ilinan light-house. — Petit Mauau Island consists of a gronp of low, rocky islets, situated about 2 miles from 

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

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



RELATIVE POSITIONS OP THE STATIONS. 



The three most southcru of the temperature stations, those at the Tortugas, Carysfort Reef, 

 and Fovrej' Rocks, are located ou the northern and western edge of a deep and coiiii)arative]y 

 narrow channel, called the Straits of Florida, which extends first easterly from the Gulf of ]\Iexico 

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

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

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

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

 slope bordering the west coast of Florida for a width of 110 to M5 miles. At Carysfort Reef, the 

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

 The deei)est water in the straits occurs at the western entrance, opposite the Tortug.is, and iu 

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

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

 Gulf Stream is felt directly upon the Florida Reefs, 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 glasses nearer the southern and eastern than the Florida side of the channel. 



The Tortugas Reefs 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, bow- 

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

 records. At Fowey Rocks, the width of the cliaiinel is reduced to about 40 miles, this width 

 being the least of any in tbe straits. The stations at Carysfort Reef and Fowey Rocks both 

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

 ascertaining the temperature of the open waters bordering the reefs. 



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

 South Carolina), a distance of about 6i degrees of latitude intervenes. Within this distance tbe 

 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, North Carolina, they retain a nearly uniform dis- 

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

 average width of about 55 miles to the 100-fathom curve, which lies ju.st 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- 

 l^ithom curve bends in somewhat toward the shore, and iu front of Cape Ilatteras tbe submerged 

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

 approaching nearer to the land. North of Cape Hatteras the 100-ftithom curve again recedes 

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



Between Georgia and Ca])o Ilatteras there are four stations, of which three arc light-ships, 

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

 tbe entrance to Port Royal Sound, South Carolina, iu front of Martin's Industry Shoal, which 

 separates the sontli and southeast clianuels; Rattletuake Shoal liglil-shi]> is just north of the 



