Water-marks on the banks of the River Darling
Becker was intrigued by the watermarks caused by the rapid changes in water levels on the Darling river banks. He makes extensive notes along the bottom of the drawing. He writes that the double action of water and wind forms inclined steps resembling stripes of land, ploughed and then partly raised up … looking like colossal sheet of musical paper.
Water-marks on the banks of the river Darling 1861.
The Darling, the Wakool and probaly[sic] some other australian rivers with their creeks have banks o peculiar that at first sight they appear to have been made and kept in repair by human hands. These banks have marks, extending form the summit to the waters edge in horizontal and parallel lines. The lines appear to one unacquainted with their origin to indicate the high water-marks of different seasons. To some extent this view is correct, but the following remarks will more fully explain the precise cause of their origin. On the 13t of Decbr 1860 the Darling reached for that year its highest point and commenced falling from that day at the rate of 5 inches in 24 hours. During the day-time seldom a calm is observed in this locality as it generally blows fresh and not unfrequently very hard. The nights, however, with few exceptions are calm and consequently the clay-soil of which the banks of the river are chiefly composed of, is washed away during the day, while at night the water is allowed to recede without disturbing the sloping ground of the river-banks, As will be seen in the drawing above this double action of the water and wind forms inclined steps resembling stripes of land, ploughed and then partly raised up to an angle of about 40 degrees-or looking like colossal sheets of musical paper. I selected for illustration the tongue of land formed by the Bamamero creek and the Darling. The broad and dark lines show where there was windy weather, the fine lines when the water was undisturbed; the dates seen on the margin of the sketch when compared with the meteorological observations of that date will be found to correspond. The drawing is an accurate sketch of the formation exhibited at the tongue of land, to which I have alluded; and my object in bringing this before the public is, to enable inquirers into geological phenomena to recognise any similar marks they may meet with in old rocks of a clayey or slaty nature.
Darling Depôt, Jan 14: 1861