Variation of the theodolite., observed on the shore of Outer Cove 7 28 east Do. of the azimuth compass, observed in the same place, 8 30 Do. of the same, taken at anchor off the port, the sloop’s head being N. by E. (magnetic), 7 44 The time of high water in Port Dalrymple, is one quarter of an hour before the moon passes over the meridian; and the rise of tide is from six to eight, or it is said to ten, feet.  The ebb sets out seven hours; and both ebb and flood run with much rapidity in the narrow parts, but the particular rate was not ascertained.

[* The longitude of Low-Head, deduced from the Investigator’s time keepers, combined with my surveys in the Francis and Norfolk, is 146 deg. 471/2 east; as the observations with the large sextant, No. 251, taken alone, would give it very nearly.]

Port Dalrymple and the River Tamar* occupy the bottom of a valley betwixt two irregular chains of hills, which shoot off north-westward, from the great body of inland mountains.  In some places, these hills stand wide apart, and the river then opens its banks to a considerable extent; in others, they nearly meet, and contract its bed to narrow limits.  The Tamar has, indeed, more the appearance of a chain of lakes, than of a regularly-formed river; and such it probably was, until, by long undermining, assisted perhaps by some unusual weight of water, a communicating channel was formed, and a passage forced out to sea.  From the shoals in Sea Reach, and more particularly from those at Green Island which turn the whole force of the tides, one is led to suppose, that the period when the passage to sea was forced has not been very remote.

[* So named by the late lieut. colonel Paterson, who was sent from Port Jackson to settle a new colony there, in 1804.  The sources of the river were then explored, and the new names applied which are given in the chart.  The first town established was Yorktown at the head of the Western Arm, but this proving inconvenient as a sea port, it was proposed to be removed lower down, near Green Island. Launceston, which is intended to be the capital of the new colony, is fixed at the junction of the North and South Esks, up to which the Tamar is navigable for vessels of 150 tons.  The tide reaches nine or ten miles up the North Esk, and the produce of the farms within that distance may be sent down the river by boats, but the South Esk descends from the mountains by a cataract, directly into the Tamar, and, consequently, is not accessible to navigation of any kind.]