For the first thirty miles of the upward course, the character of the river undergoes but little change. The left side continues bold, with the exception of a few extensive flats, sometimes overflowed, and a remarkable rocky elevation, about twenty-five miles up, to which we gave the name of The Fort, as suggested by its bastion-like appearance, though now called Table Hill in the chart. To the right the shore remains low, studded with mangroves, and still, from appearance, subject to not unfrequent inundations: towards the mouth, indeed, it is partially flooded by each returning tide. Thirty-five miles from its mouth its whole appearance undergoes the most striking alteration. We now enter the narrow defile of a precipitous rocky range of compact sandstone, rising from 4 to 500 feet in height, and coming down to the river, in some places nearly two miles wide, in others not less than twenty fathoms deep, and hurrying through, as if to force a passage, with a velocity sometimes not less than six miles an hour. NATURE OF THE COUNTRY. It continues a rapid stream during its passage through this defile, an extent of some thirty miles, and beyond it is found slowly winding its way towards the sea across a rich alluvial plain, fifteen miles in width. Above this plain is found a second range of similar character and formation to that before mentioned; the stream, however, having of course somewhat less both of width and depth, and flowing with a decreased rapidity. The elevation of the hills on either side was at first entering considerably less than in the former range; they had also lost much of their steep and precipitous appearance; but as we gradually proceeded up, the former distinctive characteristics returned: the hills rose higher and more boldly, almost immediately from the water's edge, and continued each mile to present a loftier and more rugged front; never however attaining the extreme altitude of the former or Sea Range. Above Reach Hopeless the width of the alluvial land, lying between the immediate margin of the river and the hills which bound its valley, considerably increased; and just in proportion as the high bold land approached the channel on one shore, it receded from it on the opposite, and left an extensive alluvial flat between that bank and the retreating hills; the whole valley, too, widened out, so that, supposing the stream at one time to have filled it from the bases of the high land on either side, it must have had a breadth above Reach Hopeless of from three to five miles, and this still increased when I last traced its presumed course beyond Mount Regret. The extreme altitude of Sea Range is from 7 to 800 feet, and of the hills last seen, near Mount Regret, from 4 to 500. The distinctive formation common to both consists in their level summits, within twenty feet of which a precipitous wall of rock, of a reddish hue, runs along the hillside. VEGETABLE PRODUCTIONS.