100 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY, 
The promontory of which Cape Grafton (Plate XXXI.) is the ex- 
tremity is interesting as being a point which but slight additional 
erosion would soon separate from the mainland. 
At the Hope Islands (Plate XXXII.) the reef may be said to have 
encroached to the fullest extent upon the flats which surround these 
islands; they rise inside of the ten fathom lino, and nre not more than 
two miles distant from the inner edge of one of the most interesting 
reef patches (Cairns Reef) of this part of the Great Barrier Reef. 
Both the Cairns and Endeavor reef flats rise from about fourteen 
fathoms, and the distance from the inner edge of the reef patches to 
the outer edge of the reef patches is about fifteen miles. The deeper 
soundings close to the inside edge of the outer reef patches vary from 
ten to twenty fathoms; the 100 fathom line is from two to three miles 
from their outer edges. 
At the Hope Islands and extending to a point west of Cape Flattery 
(Plate XXXIII) begin a series of reef patches which have been more 
carefully surveyed than those more to the south, so that at cortain 
stretches of this part of the coast our knowledge of the topography 
of the reef flats and patches, extending the whole width of the reef, is 
fairly complete. 
The only rocky islands within the ten fathom line are the Low and 
Rocky Islets, and in addition we find within and outside the ten fathom 
line a series of reef patches and reef flats which from their position and 
condition we may fairly assume to be the remnants of former islands 
once a part of the mainland and now covered on their surface mainly 
with dead corals, while the slopes are covered with more or less flourish- 
ing belts of coral extending to between the seven to ten fathom belt. These 
reefs are, beginning at the Hope Islands (Plates XXXII. to XXXIV.), 
successively lettered from Eh (a) Reef to En (n) Reef, a reef patch lying 
to the north of the Turtle group. Some of the larger patches, such 
as e Reef, Turtle Reef, Aitch (h) Reef, El (1) and Em (m) Reefs, and 
Eagle Reef, all of which are well isolated reef patches rising from 
twelve to fourteen fathoms in the channel between the inner edge of 
the Great Barrier Reef and the mainland. These patches undoubtedly 
represent the eroded flats of former islands, some of them of consider- 
able size, which oceupied the main part of the coast channel, much 
as the group of the Lizard Islands, the Turtle group, and the Rocky and 
Direction Islands now do. 
From the Hope Islands to off Cape Bedford (Plates XXXIT., XXXIII.) 
the width of the Barrier Reef patches varies from twelve to fifteen miles. 
