Land is about ten per cent. higher than at Parramatta, and is advancing rapidly in price. This circumstance is chiefly attributable to the small quantity of land that is to be had perfectly free from the reach of the inundations, to which the Hawkesbury is so frequently subject. These inundations often rise seventy or eighty feet above low water mark; and in the instance of what is still emphatically termed "the great flood," attained an elevation of ninety-three feet. The chaos of confusion and distress that presents itself on these occasions, cannot be easily conceived by any one who has not been a witness of its horrors. An immense expanse of water, of which the eye cannot in many directions discover the limits, every where interspersed with growing timber, and crowded with poultry, pigs, horses, cattle, stacks and houses, having frequently men, women, and children, clinging to them for protection, and shrieking out in an agony of despair for assistance:--such are the principal objects by which these scenes of death and devastation are characterized. These inundations are not periodical, but they most generally happen in the month of March. Within the last two years there have been no fewer than four of them, one of which was nearly as high as the great flood. In the six years precedings there had not been one. Since the establishment of the colony they have happened upon an average, about once in three years. The principal cause of them is the contiguity of this river to the Blue Mountains. The Grose and Warraganbia rivers, from which two sources it derives its principal supply, issue direct from these mountains; and the Nepean river, the other principal branch of it, runs along the base of them for fifty or sixty miles; and receives in its progress, from the innumerable mountain torrents connected with it, the whole of the rain which these mountains collect in that great extent. That this is the principal cause of these calamitous inundations has been fully proved; for shortly after the plantation of this colony, the Hawkesbury overflowed its banks, (which are in general about thirty feet in height), in the midst of harvest, when not a single drop of rain had fallen on the Port Jackson side of the mountains. Another great cause of the inundations, which take place in this and the other rivers in the colony, is the small fall that is in them, and the consequent slowness of their currents. The current in the Hawkesbury, even when the tide is in full ebb, does not exceed two miles an hour. The water, therefore, which during the rains, rushes in torrents from the mountains cannot escape with sufficient rapidity; and from its immense accumulation, soon overtops the banks of the river, and covers the whole of the low country. LIVERPOOL.