190 NORTH AUSTRALIAN EXPEDITION. [Nov. 10, 1856. 



supplies, and thence to the Albert River to co-operate with the land 

 expedition. 



The greatlj^ reduced number of horses, and the impracticability 

 of employing the drays for the conveyance of stores, have rendered 

 necessary a modification in the manner and arrangement of the ex- 

 ploring parties, and on the present occasion I shall employ a party of 

 seven persons, as it is desirable that the party should not be entirely 

 dependent on the assistance of the vessel at the Albert Eiver. 



The remainder of the exploring party will proceed in the schooner 

 to the Gulf of Carpentaria, and on the junction at the Albert River of 

 the two sections of the Expedition, the party will be reorganised, 

 and, if practicable, continue the overland route to Moreton Bay. 



Enclosed I transmit a sketch * of the country traversed by the 

 Expedition to the present time, and, as it may render it more 

 intelligible, append a few remarks on the physical character of the 

 country. 



It may be considered to be a table-land of sandstone rising ab- 

 ruptly from the low land on the coast ; it attains an average level of 

 700 feet on the banks of the Victoria in lat. 11° S. ; 900 feet in lat. 

 16°; 1600 feet in lat. 18°, which is the maximum, as the country 

 falls to 1300 in 19°, and 1100 feet in lat. 20©. 



The upper bed of sandstone is about 300 feet thick, and rests on 

 soft white, green, and red shales, which are superincumbent on a 

 coarse cherty limestone, and jasper. Large tracts of these two upper 

 strata have been removed, and left large valleys and plains through 

 which the rivers run. South of lat. 16° 30' trap or basalt has been 

 poured out into these valleys and formed plains or table-topped hills, 

 sometimes isolated, but more commonly grouped together. «. 



The sandstone, by its decomposition, usually forms a poor sandy 

 soil, but occasionally fine grassy plains. The limestones, which 

 occupy large extents of the valleys, are generally covered with a 

 light loamy soil, producing abundance of grass ; but the richest soil 

 results from the decomposition of the trap rocks, which are so largely 

 developed in the upper valleys of the Victoria, that at a moderate 

 computation, they occupy a million of acres. This, added to the good 

 country on the head of Sturt Creek, the lower part of the Victoria, 

 and the Fitzmaurice, would make an aggregate of three million acres 

 of available grazing land, already traversed by the Expedition. 



Except iron ore, which is frequent, minerals are rare, only few 

 traces of copper and slight indications of coal being observed. 



Of the vegetable productions, little favourable can be said, for 

 however interesting many of the plants may be to the scientific 



* In the Map-room of the Society.^— E©. 



