The river has been winding the whole day among hills, varying in elevation from 500 to 1,500 feet (estimated), and clothed with a fine forest. At the distance the Sertab hills appear to be a single range, but in fact they are a succession of short ones. When this district was inhabited, no doubt each had a distinct name, but now they call them all the Sertab hills. We are about to leave the sandstone country. In the last reach I applied the test to the first piece of limestone I have seen during this expedition, but it was scarcely necessary, as there was no mistaking its form. The Salindong hills ahead of us are evidently limestone. We had a partial view of a high mountain, which Japer says is the east end of the Molu range, which I long to see in the rear, but as yet it is always to the east of south. I suspect there are several ranges, forming what the natives call the Molu hills. The general direction from the mouth of the Madalam has been S.E. by E. The incidents which have varied the day have been the finding of another new Kayan sulap, or hut, and the decaying head of a large wild boar left by an alligator on the bank. The last was for us an unfortunate discovery, as the Muruts seized upon it, and have it now in their boat--a most offensive subject for our nostrils. Every time they passed us a most disgusting whiff came our way, and now at our resting place we are obliged to insist that they shall either get rid of the head, or encamp away from us. The love of high pork has prevailed over fear, so they have taken up their quarters at the other end of the pebbly flat. I have noticed to-day many of those deep holes in rocks mentioned by De la Beche, as caused by the continual working of pebbles on them. Many have bored their way down several feet, working even through to the stream; others are in every stage of progress. The river, though in many places deep, is generally shallow, particularly at the rapids, and it occasionally rushes down with great force. I expect as we enter the limestone district, to change the character of these impediments, which have as yet consisted of pebbles, gradually enlarging as we move up the river; many of limestone are now showing themselves. The Muruts declare there are edible birds’-nest caves near Salindong; but we must reserve any search till our return, as I will not allow anything to interfere with our advance.