feet above the sea. In regard to the size of volcanic craters, it might be said that in the eastern part of the island of Java a crater is to be found twelve to fifteen. miles in circumference; that of Kilauea does not exceed nine miles. On the eastern peninsula of the island of Maui, one of the Sandwich group, is located the summit crater of Mauna Haleakala, 10,200 feet above the sea level. Following the rim of the once fiery cauldron, the circumference is all of twenty-seven miles, while the depth from the edge to the bottom of the great pit is two thousand feet. As far as known, this is the largest volcanic crater in the world. Kilauea, Dana says:

Of

BURNING LAKE OF KILAUEA.

Kilauea is a deep pit in the sides of Mount Loa. The gentle slopes of the dome in this part scarcely vary from a plain, and the crater appears like a vast gulf excavated out of the rock-built structure. Although there is no cone, the country around is slightly raised above the general level, as if by former eruptions over the surface; but this is hardly apparent without extended and careful examination.

The traveler perceives his approach to the crater in a few small clouds of steam rising from fissures not far from his path. While gazing for a second indication, he stands unexpectedly upon the brink of the pit. A vast amphitheatre, seven miles and a half in circuit, has opened to view. Beneath a gray, rocky precipice of 650 feet, forming the bold contour, a narrow plain of hardened lava (the “black ledge") extends like a vast gallery around the whole interior. Within this gallery, below another similar precipice of 340 feet,

lies the bottom, a wide plain of bare rock more than two miles in length.

One

The eye naturally ranged over the whole area for something like volcanic action, as it is usually described. But all was singularly quiet. In the dark plain that forms the bottom there was little to attract attention beside the utter dreariness of the place, excepting certain spots of a blood-red color, which appeared to be in constant yet gentle agitation. Instead of beholding a sea of molten lava "rolling to and fro its fiery surge and flaming billows," we were surprised at the stillness of the scene. The incessant motion in the blood-red pools was like that of a cauldron in constant ebullition. The lava in each boiled with such activity as to cause a rapid play of jets over its surface. pool, the largest of the three then in action, was afterwards ascertained by survey to measure 1,500 feet in one diameter, and 1,000 in the other; and this whole. area into which the capitol grounds at Washington might be sunk entire was boiling, as seemed from above, with nearly the mobility of water. Still all went on quietly. Not a whisper was heard from the fires below. While vapors rose in fleecy wreaths from the pools and numerous fissures, and above the large lake they collected into a broad canopy of clouds, not unlike the snowy heaps or cumuli that lie near the horizon on a clear day, though changing more rapidly their fanciful shapes. On descending afterwards to the black ledge at the verge of the lower pit, a half-smothered, gurgling sound was all that could be heard from the pools of lava. Occasionally there was a report like that of musketry, which died away and left the same murmuring sound-the stifled mutterings of a boiling fluid. Such was the appearance of Pele's pit in a day

view, at the time it was visited by the author (in November, 1840).

At night, though less quiet, the scene was one of indescribable sublimity. We were encamped on the edge of the crater, with the fires in full view. The large cauldron, in place of its bloody glare, now glowed with intense brilliancy, and the surface sparkled with shifting points of dazzling light occasioned by the jets in constant display. A row of small basins on the southeast side of the lake were also jetting out their glowing lavas. Two other pools in another part of the pit tossed up their molten rock much like the larger cauldron, and occasionally burst out with jets forty or fifty feet in height. The broad canopy of clouds above the pit, which seemed to rest on a column of wreaths and curling heaps of lighted vapor, and the amphitheatre of rocks around the lower depths, were brightly illuminated from the boiling lavas, while a lurid red tinged the distant parts of the inclosing walls, and threw into shades of darkness the many cavernous recesses. And over this scene of restless fires and fiery vapors, the heavens, by contrast, seemed unnaturally black, with only here and there a star like a dim point of light. The next night streams of lava boiled over from the lake, and formed several glowing lines diverging over the bottom of the crater. Towards morning there was a dense mist, and the whole atmosphere seemed on fire. Through the haze the lakes were barely distinguished by the spangles on the surface that were brightening and disappearing with incessant change.

ISLAND FORMATION.

Among the groups of Polynesia the Hawaiian exceeds all others in geological interest. The agency

of both fire and water in the formation of rocks is exemplified not only by results, but also by processes now in action, and the student of nature may watch the steps through the successive changes. He may descend to the boiling pit and witness the operations in the vast laboratory with the same deliberation as he would examine the crucible in a chemist's furnace. Thus the manner in which mountains are made and islands built up becomes a matter of observation. The volcanic dome may be seen in process of accumulation from overflowing lavas, and may be traced as it increases in size. Again, disruptions of the accumulated rock may be observed, followed by their disappearance in the lavas below.

While these volcanic mountains are still extending their limits in one part of the group, in others those changes are finely illustrated, which they undergo through the action of water, gradual decomposition and other allied causes, and these effects are in every stage of progress. In some instances the slopes retain the even surface of the lava stream; in others, they are altered in every feature-the heights are worn down, the whole surface gorged out with valleys, and the depth of these furrowings of time, indicate that the several islands differ widely in the length of the period since they were finished by the fires and left to the action of the elements.

Moreover, the coral formations of the shores present us with reefs now in progress from the growing zoophytes, and there are also reefs elevated many feet above the sea, having a close resemblance to beds of limestone. Besides these, there are hills of drift sandrock, of coral origin. The various facts illustrate, therefore, all the results of coral growth and accumulation.

The group is consequently the key to Polynesian geology. It combines all the features which are elsewhere widely scattered, and they are so exhibited in progressive stages as to afford mutual illustration. An island like Tahiti, so broken into peaks and ridges, may excite wonder and doubt. The Hawaiian group suggests the same difficult problem as Tahiti, but an intelligent solution is at the same time presented for our contemplation and study.

(Dana, Geol., Wilkes' Exp. Expedition.)

ISLANDS PACIFIC COAST OF SOUTH AMERICA.

Off the west coast of South America there are at least 300 islands, becoming more numerous and in larger groups as we go towards Cape Horn.

Those off the coast of Ecuador, the Albemarle, James, Chatham, Indefatigable, Hood, Charles, Narboro, etc., have already been alluded to in this work, under the head of Galapagos.

GUANO.

Lying near the coast of Peru, and only about twelve miles from the main land, between 13 deg. and 14 deg. south latitude, and containing but a few square miles of area, are the celebrated guano group, the Chincha Islands. It may not be unininteresting to state here, that nearly 20,000,000 tons gauno have been exported to Europe and America from this little group alone. The shipments were commenced in 1841, and continued on a scale of great magnitude up to 1872, when the guano deposits were practically exhausted. Between the years 1853 and 1872,