Country between Morelon Bay and Port Essington. 91 
the action of these two currents of air when they meet and mix. 
About 10—11 o’clock at night, a veil of loose clouds formed sud¬ 
denly to the southward, and rose rapidly witli a strong puff of 
southerly wind ; another mass of clouds formed in the same 
quarter, and passed as rapidly as the first, and after that a strong 
full breeze set in from the southward, with a perfectly clear sky. 
According to the Rev. Mr. Clarke, something similar takes place 
over Sydney, about sundown, in the summer season, but is suc¬ 
ceeded by a still night. 
The bracing nature of the south breeze at night, had a very 
beneficial influence on our constitutions; as the regular inter¬ 
change of land and sea breeze contributes every where to render 
a climate healthy. 
7. The seventh division of my route is formed by the Roper 
and by the high land of Arnlieim’s Peninsula. The Roper is the 
only large fresh-water river of the west coast of the gulf, as far 
as we followed it to the northward. It is fed by a great number 
of running creeks and brooks, all closely fringed by belts of pan- 
danus. Almost the whole country along the river was open, well 
grassed, and available for depasturing purposes. At its upper 
course exist fine plains, which are bound by sandstone ridges, and 
diversified by pandanus creeks, forming an extremely pleasing 
landscape. The high land was covered with an open stringy-bark 
forest on a sandy soil, but its level is frequently interrupted by 
steep rocky sandstone hills and ridges, at the foot of which tea- 
tree swamps, with a peaty soil, formed frequently the heads of 
creeks. 
I have mentioned that the fall of the high land of the York 
Peninsula is more sudden to the westward ; the same is the case 
in a still higher degree in Arnheim’s Land, for there is not only a 
very rapid fall in the creeks, but there are precipices 500—800 
feet high, which border the valley of the South Alligator River, 
and over which numerous cascades rushed down to join their 
waters with those of that river. 
It was very remarkable that the only slope which allowed us to 
descend into the valley is formed by granite, whereas the whole of 
Arnlieim’s land and the ranges of the Roper are composed of 
