52 EXPLORATION OF THE MURCHISON, LYONS, AND [Nov. 8, 1858. 



to granite and gneiss, frequently broken up by the upheaval of whin- 

 stone and porphyritic trap hills, having an elevation of from 100 to 

 500 feet above the plain. 



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 G feet per mile : this, in a country subject to the sudden fall of 

 almost tropical rains, is what gives rise to the destructive inunda- 

 tions already described. 



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 Mur- 

 chison, until the country has again been visited at a different period 

 of the year, as it is probable 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*^ in six hours, 

 registering at 7 a.m. 36°, and at 1 p.m. 82° ; ice having been seen as 

 far north as lat. 24° 30'. 



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 the}^ cannot be relied on with any 

 degree of certainty to the southward of the 25th degree of lat., the 

 period at which they fall being about January and February ; and 

 it is a significant fact that the grass found buried beneath the mud 

 during these months, had generally attained only about half its 

 growth. 



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 



