THE NORTH-AUSTRALIAN EXPEDITION. 209 



1600 feet in lat. 18°, which is the maximum, as the country falls to 

 1300 in 19°, and 1100 feet in lat. 20°. 



49. 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. 



50. 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 by a light loamy soil, 

 producing abundance of grass ; but the richest soil results from 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's Creek, 



the lower part of the Victoria and the Fitzmaurice Kiver,— would 

 make an aggregate of at least 3,000,000 acres of available grazing land 

 already traversed by the Expedition. 



51. Except iron ore, which is frequent, minerals are rare, only 

 a few traces of copper and slight indications of coal having been ob- 

 served. 



52. Of the vegetable productions little favourable can be said ; for, 

 however interesting many of the plants may be to the scientific botanist, 

 yet, with the exception of the Grasses, which are very numerous, there 

 is scarcely a single vegetable production which can be rendered practi- 

 cally useful ; timber is scarce— the best growing near Point Pearce. 



53. In conclusion, it gives me pleasure to record the ready co-opera- 

 tion and assistance I have experienced on the part of the officers, and 

 the exemplary conduct of the men attached to the Expedition, and 

 that under circumstances of privation which few who have not expe- 

 rienced them can fully appreciate. 



I have the honour to be, Sir, your obedient Servant, 



A. C. Gregory. 



His Excellency the Governor- General of Australia 



(To be continued.) 



VOL. IX. 



2 E 



