From the shore line, out to a distance which may be anywhere from a few miles to a few hundred miles.

From the shore line, out a distance which may be anywhere from a few miles to a few hundred miles, runs the gentle slope of the continental shelf, geologically part of the continents.

This continental slope usually starts at a place somewhere near the 100-fathom mark and in the course of a few hundred miles reaches the true ocean-floor at 2,500-3,000 fathoms.