11 April

We left this camp (named Camarba) and continued our journey around the  great bend of the Lachlan at which point (4 1/2 miles from our camp) the  low ridge of Kalingalungaguy closed on the river. This ridge is a  remarkable feature, extending north and south, and I expected to see some  tributary from the north entering the river here; but we crossed on the  east side of the ridge only a wide, dry and grassy hollow, which was  however evidently the channel of a considerable body of water in times of  flood, as appeared by marks on the trees which grew along the banks. All  were of the dwarf box kind, named goborro by the natives, a sort of  eucalyptus which usually grows by itself on the lower margins of the  Darling and Lachlan, and other parts subject to inundation, and on which  the occasional rise of the waters is marked by the dark colour remaining  on the lower part of the trunk. In the bed of the Lachlan at the junction  of the channel near Kalingalungaguy I found quartz rock.

We had not proceeded far beyond that ridge when Mr. Stapylton overtook  the party, having travelled in great haste from Sydney to join us as  second in command, in compliance with my letter of instructions sent from  Buree. Mr. Stapylton was accompanied by two stockmen, having left his own  light equipments at Cordowe, a station above Mount Cunningham. On the  plains which we crossed this day grew in great abundance that beautiful  species of lily found in the expedition of 1831, and already mentioned  under the name of Calostemma candidum,* also the Calostemma luteum of Ker  with yellow flowers.
(*Footnote. Volume 1. C. candidum; floribus centralibus subsessilibus,  articulo infra medium in pedicellis longioribus, corona integerrima.)

At nine miles we crossed some granite rocks, evidently a part of the  ridge of Tarratta, thus exhibiting a uniformity in the granite with the  general direction of other ridges, which is about north-north-east. The  strike is between north and north-east; the dip in some places being to  the west, and in others to the east, at great inclinations. The ridge of  Kalingalungaguy consists of quartz, clay-slate, and the ferruginous  sandstone, but I observed in the bed of the river a trap-dyke extending  to the Bolloon ridge. Of the few low hills about the Lachlan it may be  observed that they generally range in lines crossing the bed of that  river. Mount Amyot is a ridge of this sort, being connected to the  southward with Mount Stewart and Nyororong; and to the northward with the  high ground separating the Bogan from the Goobang; the latter creek also  forcing its way through the same chain on its course westward. Mounts  Cunningham, Melville, and the small hills about them on each bank belong  to another system of ridges of similar character, but more broken up; and  the range of Kalingalungaguy with that of Bolloon form a third, also  intersected by the river.

The plains appear to be divided into several stages by these cross  ridges, which may have shut up the water of high floods in extensive  lakes during the existence of which the deposits formed the surface of  the present plains. Loose red sand also constantly forms low hills on the  borders of these plains; and it seems to have been derived from the  decomposition of the sandstone, and may be a diluvial or lacustrine  deposit. Blue clay appears in the lowest parts of the basin, and forms  the level parts of the plain, with concretions of marl in thin layers.  This has every appearance of a mud deposit; but its depth is greater than  the lowest part visible in the channel of the river. The parallel course  of small tributaries joining rivers, which seem to be the middle drain of  extensive plains, may have been marked out during the deposition of the  sedimentary matter as tributaries, on entering the channel of greater  streams, immediately become a portion of them; hence it is, the general  inclination being common to both, that such tributaries do not cross  these sediments of floods now termed plains in order to join the main  channel or river now remaining.

Thus the Goobang, on entering the valley of the Lachlan, pursues a  parallel course until the ridge from Hurd’s peak confines the plain on  the west and turns the Goobang into the main channel. The Bogan, on the  opposite side of the high land, may be said to belong to the basin of the  Macquarie, although it never joins that river, but merely skirts the  plains which, below Cambelego, may be all supposed to belong to the  original bed of the Macquarie. Throughout its whole course of 250 miles  the left bank of the Bogan is close to low hills, while the right adjoins  the plains of the Macquarie. The basin of the Macquarie, as shown by its  course near Mount Harris and Morrisset’s ponds, falls northward, but that  of the Darling to the south-west. It is not at all surprising therefore  that the course of a tributary so much opposed, as the Macquarie is, to  that of the main stream, should spread into marshes: still less that, on  being at length choked with the deposit filling up these marshes, it  should work out for itself a channel less opposed to the course of the  main stream. Duck creek appears to be now the channel by which the floods  of the Macquarie join the Darling, and in a course much more direct than  that through the marshes. Hence the Bogan also, being still less opposed  to that of the Darling, finally enters that river without presenting the  anomaly of an invisible channel. In like manner, at a much lower point on  the Darling, the course of the little stream named Shamrock ponds, so  remarkable in this respect, may be understood. This forms a chain of  ponds, or a flowing stream, according to the seasons, between the plains  on the left bank of the Darling, and the rising grounds further to the  eastward: but instead of crossing the plains to join the main channel  this supposed tributary, after approaching within one or two miles of the  Darling where its plains were narrow, again receded from it as they  widened, and finally disappeared to the left where the plains were broad,  so that its junction with the Darling has not even yet been discovered.  On this principle the channel of the Lachlan, as soon as it enters the  plains belonging to the basin of the Murrumbidgee, may be sought for on  the northern skirts of these plains, although its floods may have been  found to spread in different channels more directly towards the main  stream.

At 12 1/4 miles we crossed a dry and shallow branch of the river, and at  14 1/2 miles we at length reached the main channel, and encamped where a  considerable pond of water remained in it, surrounded by abundance of  good grass. In this hole we caught some cod-perch (Gristes peelii).