290) J. EB. Hilgard—Basin of the Gulf of Mexico. 
depth of the Gulf to be reduced by 100 fathoms, a surface 
would be laid bare amounting to 208,000 square miles, or 
rather more than one-third of the whole area. The distance 
of the 100 fathom line from the coast is about six miles near 
Cape Florida; 120 miles along the west coast of Florida; at 
the South Pass of the Mississippi it is only 10 miles; opposite 
the Louisiana and Texas boundary it increases to 130 miles; 
at Vera Cruz it is 15 miles, and the Yucatan Banks have about 
the same width as the Florida Banks. 
The following table shows the areas covered by the trough 
of the Gulf to the depths stated : 
: Area. Differences. 
2,000 fathoms 55,000 square miles 
1,500 fathoms 187,000 square miles 132,000 
1,000 fathoms 260,000 square miles 73.000 
500 fathoms 326,000 square miles 66,000 
100 fathoms 387,000 square miles 61,000 
Coast line 595,000 square miles 208,000 
depths of 100 and 1,500 fathoms. The maximum depth reached 
is at the foot of the Yucatan Banks—2,119 fathoms. From the 
1,500 fathom line on the northern side of the Gulf to the deep- 
est water close to Yucatan Banks, say to the depth of 2,000 
fathoms, is a distance of 200 miles, which gives a slope of five- 
ninths to 200, and may be considered practically as a plane 
surface. 
The large submarine plateau below the depth of 12,000 feet 
has received the name of the “ Sigsbee Deep,” in honor of 1ts 
discoverer. 
The Yucatan channel with a greatest depth of 1,164 fathoms 
has a cross section of 110 square miles, while the strait of 
Florida in its shallowest part opposite Jupiter Inlet, with a 
de th of 344 fathoms, has a cross section of only 11 square 
iles. 
A view of the model reveals at once some important facts 
which a study of the plan only conveys imperfectly to the 
mind, and which were unsuspected before this great explora- 
tion wascompleted: Thus the distance between the visible coast 
lines of the northeastern point of Yucatan and the west coast 
of the Florida Peninsula is 460 miles, while the distance be- 
tween the submerged contours of 500 fathoms is only 190 
miles; between the contours of 1,000 fathoms only 90 miles. 
These facts at once characterize the Gulf of Mexico asa Med- 
iterranean Sea. 
The most striking features displayed by the model are the 
following : 
. The great distance to which the general slope of the 
continent extends below the present sea level before steepe? 
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