Although Booby Island is a mere rock, from the various associations connected with it, being during one half of the year the constant resort of Europeans, it becomes at once a place of interest, and imperatively demands some notice at our hands. It is a quarter of a mile in diameter, flat, and about thirty feet high, the summit being bare porphyry rock. A valley intersects the north-west side of the island, in which a few creepers, some brushwood, and two or three trees of tolerable size, with a peculiar broad green leaf, bearing a great resemblance to that of the wild almond of the West Indies, were seen, giving shelter to some pigeons and quails, in which latter the island abounds, even more than in the bird which gives its name to the locality. Still, however, from the white colour of the top of the island, produced by the boobies, it is clearly one of their temporary haunts; and indeed, subsequently, in the month of September, their season of incubation, Mr. Bynoe saw them there in great abundance. The contrary was the case with the quail, which, by that time, had completely deserted the island. Turtle were once found on this isle, but they are now never taken. A few of the stones mentioned by Captain King are still to be seen on the summit.
REMARKS ON THE CORAL REEFS OF AUSTRALIA.
This being a point at which ships correct or test the going of their chronometers, it was necessary to obtain observations for longitude. The spot chosen for the purpose was the landing-place near the South-West corner of the islet, and which we found to be 9 degrees 45 minutes East of Port Essington.
Our opportunities of examination with regard to the inner edge of the Great Barrier, and its contiguous islands and reefs, terminating at Booby Island; it may not be deemed irrelevant to hazard a few remarks in recapitulation. In the first place there was a very perceptible increase in the elevation of the reefs and of those islands resting on similar constructions, as we advanced to the northward. Cairncross Island, in latitude 11 1/4 degrees South, composed of heaped up consolidated fragments, attains an elevation of 17 feet; but its trees rise to a height of 75 feet, whilst to the southward, in latitude 13 1/2 degrees South the islands were partially flooded by a tide, rising only about six feet. The reefs are all either circular or oval-shaped, with a rim rising round them. The description of that fronting the isle we visited for Boydan will illustrate their general character. Their northern ends are the highest, and are almost invariably marked by a heap of dead coral and shells, which as we have mentioned, in one or two instances, from its white appearance has often been taken for sand.
The remarkable breaks in this singularly great extent of coral reefs, known as the Barrier of Australia, being in direction varying from West to West-North-West generally speaking North-West, leads me to believe that the upheaval by which the base of this huge coral building was formed, partakes of the general north-westerly direction, in which a large portion of the eastern world apparently emerged from the water. A glance at the map of that portion of the globe, will strengthen this hypothesis, placing as it does this singular fact at once before the reader's mind. Starting with the stupendous heights of the Himalaya mountains, and proceeding thence to several groups of the Polynesian islands, New Caledonia, and others, this remarkable similarity in the trend of these portions of the earth is plainly distinguishable. It would appear, therefore, from the general north-westerly tendency of these upheavals, that the cavernous hollows beneath the crust of the earth, within whose bosom originated these remarkable convulsions, have a strong inclination in one direction, a circumstance in connection with the earth's history of great and curious interest. With this general statement of facts, which we note for the benefit of scientific men, and in illustration of the singular changes which are taking place on the surface of the globe, we return to our narrative, from which we have wandered at some considerable length.
As the duration of our cruise on the north-west and most interesting portions of the coast, depended in a great measure on the supply of provisions to be obtained at Port Essington, we were naturally anxious to satisfy ourselves upon the point, and accordingly spent but a few hours at Booby Island, taking our departure at 8 P.M. on the day of our arrival.
PROCEED TO PORT ESSINGTON.
Proceeding towards Port Essington, we experienced a constant current setting between North-West and West, from half to three quarters of a knot an hour, except when crossing the mouth of the Gulf of Carpentaria, when from the indraught its direction was changed to West-South-West. The winds were as Captain King has described them, veering from South-South-East in the morning, to East in the evening, and blowing fresh towards the middle of the day.
Beyond this nothing occurred worthy of remark, until the morning of the 17th, when soon after daylight we found ourselves steering rather within a large patch of discoloured water, extending off Cape Croker, the North-East extreme of the Coburg Peninsula, a low point with a slight hummock on it; on the north side of this peninsula is situated Port Essington, thirty miles to the westward of the Cape.
CAPE CROKER REEF.