MOUNT LOA, HAWAIL 207 
direction, and one near the west bank had ejected lavas at no distant 
period. Two cinder cones at the bottom, consisting of light scoria, 
were remarkably perfect in form, and one was two hundred feet high. 
About many of the fumaroles, there were the same salts that occur at 
the sulphur banks of Kilauea. 
Besides the large pit, there are two others, one on the north, and 
another on the south, called Pohakuo-hanalei,* both of which may be 
looked upon as subordinate to the central one, as they are enclosed 
within the same general rim or outline. There is also another small 
pit, distinct from these, a short distance to the south. 
Into Pohakuo-hanalei, a stream of lava had run from Mokua-weo- 
weo; and Captain Wilkes remarks, that it looked like a cascade of iron 
which had become solid before reaching the bottom. ‘There were 
several deep fissures in the vicinity of this pit, and every appearance 
of recent eruptions. “The lava at the mouth of some of the chasms 
appeared as though it had been thrown up and plastered on the edges 
in clots, which seemed of the consistency of tar or melted sealing-wax 
of various colours, the most predominant a dark brown.” 
There were several small cones about the summit, both to the north 
and south of Mokua-weo-weo. 
The rocks of the summit, where there was evidence in their appear- 
ance of recent origin, resembled those of modern ejections below. But 
the walls of the crater are described as consisting of a compact grayish 
rock, without cellules, and often breaking in plates. The specimens 
obtained were a grayish clinkstone, speckled with a white feldspar, 
with no trace of a cellule, and no resemblance to ordinary lavas. 
They consist mostly of the feldspar. 
Within caverns about the crater, mammillary concretions of a 
hydrous silicate of alumina were obtained, which had resulted from 
the decomposition of the rock. 
These concretions have been-examined chemically by Prof. B. Sil- 
liman, Jr., who obtained the following for their composition :+ 
* Pronounced Pohah-koo-o-hahnalay. 
t “ Pyrognostic Characters.—In an open tube gives off a small quantity of water, which 
promptly and fugaciously reddens litmus paper. Emits, when heated, an empyreumatic 
odour, In thin scales, in platinum forceps, it fuses into a white transparent frit. Dis- 
solves in carbonate of soda, and in borax forms a clear and colourless bead. With 
caustic soda alone, ina dry test tube, it reacts vigorously on heating, forming a complete 
solution. Effervesces strongly in hydrochloric acid from escape of carbonic acid, and 
leaves a white insoluble residue. The quantitative examination proved the presence of 
silica, lime, water, soda, potash, carbonic acid, alumina, and iron, A large and gritty 
