As we proceeded eastward, the eruptive rocks became more numerous; chlorite slate, veins of quartz, chert, and variegated jasper, frequently forming the summits of the most elevated hills, while, on the general level of the plain, are occasionally found thin beds of ancient lava.

The rivers, unlike most others in Western Australia, have nearly an even fall throughout their entire length, amounting on an average to six feet per mile; this, in a country subject to the sudden fall of almost tropical rains, is what gives rise to the destructive inundations already described.

Climate.

Of the climate and seasons so little is at present known that, allowing all other difficulties to have been overcome, it would be very hazardous to risk flocks and herds beyond the head of the Murchison until the country has again been visited at a different period of the year, as it is probably that it has as yet only been seen under the most favourable conditions.

The fluctuations of the temperature are occasionally considerable; in the middle of June it some days amounted to 46 degrees in six hours—­registering, at 7 a.m., 36 degrees, and at 1 p.m., 82 degrees; ice having been seen as far north as latitude 24 degrees 30 minutes.

The prevailing winds during the period of inundation appear to have been from the south-east, as most of the trees blown down while the soil was in a state of saturation lay with their tops to the north-west.  In May and June the winds ranged between north-east and south-east.

Of the regularity of the return of the summer rains it is at present difficult to form a decided opinion; but, as far as observation would admit, I am inclined to think they cannot be relied on with any degree of certainty, to the southward of the 25th degree of latitude.  The period at which they fall being about January and February, it is a significant fact that the grasses found buried beneath the mud during these months had generally attained only to nearly half their growth.

Area of available country.

With regard to the quantity and distribution of the available lands, it will only be necessary to observe that, with the exception of 30,000 or 40,000 acres at the mouth of the Gascoyne, there is no land worth occupying for many years to come to the west of the Lyons River; the amount of land on this river has already been estimated at nearly 300 square miles, while on the Upper Gascoyne and its tributaries there is probably double that quantity; this, with the lands on the Murchison near Mount Hale, would make a total of about a million of acres.

A very important circumstance in connection with this district is the total absence, so far as we were able to observe, of any of the varieties of gastrolobium or euphorbia, which constitute the poisonous plants so fatal to cattle and sheep in other parts of the colony.