During our absence Mr. Roe, who was fast recovering from the effects of his fall, had obtained the sun's meridional altitude upon the islet at the entrance of the river, which gave 15 degrees 25 minutes 46 seconds for its latitude, differing from the plan of last year by only fifteen seconds. July 27. The following day the boats were despatched up the river, but as the ebb-tide ran until after four o'clock it was late at night before they reached the cascade, having experienced some delay by running upon the sandbanks, which, above Alligator Island, are very numerous and form a narrow winding channel of not more than twelve feet deep; these banks are dry at low-water, and are composed of a yellow quartzose sand. At midnight, as soon as the launch and cutter were loaded, for it did not take more than half an hour to fill the casks, I despatched them to the vessel with orders to return the following night for another load, and in the meantime I purposed continuing the examination of the river, of which we knew nothing beyond a few miles above the cascade. July 28. We were, however, unable to set out until half flood the next morning, on account of the shoalness of the channel. For ten miles we found little or no variation either in its character or course: its windings were only just sufficient to intercept a clear view; for so direct was its course, that from this part the high round hill near the entrance was seen midway between the hills that form the banks of the river. Proceeding a little way farther, we were suddenly whirled into a rapid amongst large stones, in the midst of which, as the stream was running at the rate of five or six knots, the grapnel was instantly dropped, which had the effect of reversing the boat's head. After this the grapnel was weighed, and by very great exertions we extricated ourselves from the rapid, and then landed at a hundred yards below the fall, on the east bank, where the mangroves were so thick that it was with difficulty we penetrated through them: having succeeded, we walked to the bank near the rapid, and found that it was occasioned by the tide falling over a barrier of rocks, which probably at low-water confines the fresh water above this place; a few minutes afterwards it was high-water, and the tide suddenly ceased to run; when the water became quite smooth and motionless.