ClI. v.] CONVENIENT REFRACTION. 239 



knolls consist of a red earth, which is different from the soil 

 of the plains ; its basis appearing to be iron-stone. We en- 

 camped on good firm ground, and there was abundance of 

 good grass on the river bank. We were not very far from 

 the heights on the opposite side; a branch from them ex- 

 tending nearly to the river. 



Jiine 21. — The ground was much better this day for tra- 

 velling over. We passed through a scrub of limited extent, 

 and for the first time, in these parts, we discovered a new 

 species of casuarina. On ascending a small hill to the left of 

 our route, I perceived two summits of a distant range, bear- 

 ing 169° 20' (from N.) ; and I was not sorry to see that the 

 intervening country was better wooded and undulated more 

 than that we had lately traversed, for wherever trees or 

 bushes grew, we generally found the ground to be hardest. 

 We were compelled to travel much further than I intended 

 in order to reach the river, which took a great sweep to the 

 west, a change in its direction which I had previously ob- 

 served to take place in the course of this river on approach- 

 ing a similar feature on the right bank. The river was nar- 

 rower, and its channel more contracted at this part than 

 at any other I had seen ; indeed, so great was the change in 

 the dimensions, that I doubted whether this was more than an 

 arm of it. The current, however, ran at about the same rate, 

 and the general course for some miles to the southward, was 

 marked out, as usual, by large trees. At the camp, the head 

 of the range on the right bank, bore N. 16° W. 



June 22. — The distant range which I observed during the 

 journey of yesterday, appeared high above the horizon of our 

 camp this morning, and the refracted image was so perfect, 

 that with my glass I could distinguish the trees, and other 

 objects. Thus I obtained bearings on the range, from a 

 spot whence it could be but seldom visible. The small emi- 

 nences to the eastward, from which I first saw that range, 

 were also refracted, and appeared like cliff's on a sea coast. 

 To the astonishment of the men, all the hills, however, soon 



