462 Mr. H. B. Guppy on Coral-soundings 
impression difficult to recognize. In section 1, I have shown, 
drawn on the true scale, the seaward slope of that part of the 
reef at which the soundings were taken. For the first 100 to 
150 yards from the edge of the reef the submarine slope was 
somewhat gradual until a depth of about 16 fathoms was 
reached, when, within a distance of two boats’ length, the 
Sections showing the Seaward Slopes of Reefs in the Solomon group. 
(Drawn on a true scale to the 100-fathom line, 5 inch=100 feet.) 
Section 1.—Port-Mary Reef, Santa Anna. 
Sea-level, 
MQ WY : 
Section 2.—Reef of Onua Islet, Shortland Islands. 
Sea-level. 
Section 3.—Barrier-reef of Choiseul Bay. 
WM 
soundings suddenly increased in depth by about 100 feet, 
or another 16 fathoms. rom the foot of this declivity there 
was an easy descent for about 450 yards, with a fall of some 
50 or 60 feet, terminating in a precipitous slope where 
there was a drop of about 25 fathoms or 150 feet. The 
submarine slope beyond descended at a moderate angle to 
considerable depths. Ihave, however, terminated this section 
Sea-level. 
