ter, and the mercury at once rose to one hundred and twenty degrees. From observations already made by myself and in company with Professor James Nooney, I now felt that I could trace the line of thermal action, and my next object was to find the seat or focus of its greatest intensity. To accomplish this I was so fortunate as to have the aid of Messrs. P. Cyrus, J. Cyrus, and B. F. Briggs, three excellent young gentlemen and experienced hunters. We travelled northwesterly from the head of Napa valley, and after encamping one or two nights in the rain, and wandering through almost impenetrable thickets, reached the summit of a high peak on the morning of the fourth day. On the west we saw the vast Pacific. On the south, the Bay of San Francisco, Mount Diabalo,* Sonoma and Napa valleys. On the southwest, the valleys of Santa Rosa and Russian river. On the east, the lofty range of the Sierra Nevada: while on the north, almost immediately at our feet, there opened an immense chasm apparently formed by the rending of the mountains in a direction from west to east. The sun's rays had already penetrated into the narrow valley and so lighted up the deep defile, that from a distance of four or five miles, we distinctly saw clouds and dense columns of steam rapidly rising from the banks of the little river Pluton. It was now the eighth of February: the mountain peaks in the distance were covered with snow, while the valley at our feet wore the verdant garb of summer. It was with difficulty we could persuade ourselves that we were not looking down upon some manufacturing city, such as Pittsburg or Wheeling, until by a tortuous descent we arrived at the spot where at once the secrets of the inner world opened upon our astonished senses. In the space of half a mile square we discovered from one to two hundred openings through which the steam issued with violence, sending up columns of dense steam to the height of one hundred and fifty to two hundred feet, like our largest ocean steamers, and gradually diminishing to engines of one or two horse power. The roar of the larger tubes could be heard for a mile or more. The sharp hissing of the smaller ones is still ringing in my ears. Many of them would work spasmodically, precisely like high pressure engines. Throwing out occasional jets or volumes of hot scalding water some twenty or thirty feet, endangering the lives of those who rashly venture too near. In some places the steam and water come in contact so as to produce a constant "jet d'eau" or spouting fountain with a deuse cloud above the spray, affording vivid prismatic hues in the sunshine.

Numerous cones are formed by the accumulation of various mineral salts and a deposit of sulphur crystals with earthy matter,

* Mount Diabolo is reported to be an extinct volcanic cone,

which often harden into crusts of greater or less strength and thickness. Frequently the streams of boiling water would mount up to the top of the cones with violent ebullition. Some of the cones appear to be immense boiling cauldrons, and you hear the lashing and foaming gyrations beneath your feet as you approach them. It is then a moment of intense interest. Curiosity impels you forward-fear holds you back; and while you hesitate, the thin crust under your feet gives way, and you find yourself sinking into the fiery maelstrom below. The writer on one occasion heard the rushing of water under his feet. He struck down an axe which on the first blow went through into the deep whirlpool the whole length of the helve. He withdrew it and cut an opening, which revealed a stream of angry water, boiling intensely and of unknown breadth and depth. He continued to enlarge the opening until the stream was seen to be five or six feet in breadth, leading on indefinitely into the dark caverns beneath the mountain. This geyser is called Agassiz's Maelstrom.

Another place where a large volume of water boils up violently and settles in a circular basin and has also a steam tube by its side, is called Silliman's Fountain. Another, is named the Panther Geyser, from the circumstance that a huge wild panther had taken up his residence on the bank of the warm mound and seemed quite unwilling to leave his comfortable habitation. Another, where the waters gyrate with a loud noise "in gurgite vasto” is called Pluto's Cauldron. Another, the Ocean Steamer, &c.

At the base of the cones, in the bottom of the ravines, and in the bed and on the north bank of the river Pluton, springs almost innumerable break out, which are of various qualities and temperatures, from icy coldness up to the boiling point. You may here find sulphur water precisely similar to the celebrated White Sulphur of Green Brier County, Va., except its icy coldness. Also red, blue and even black sulphur water, both cold and hot. Also pure limpid hot water without any sulphur or chlorine salts, calcareous hot waters, magnesian, chalybeate, &c., in almost endless variety. Every natural facility is afforded for either vapor, shower or plunging baths. Where the heated sulphuretted hydrogen gas is evolved, water appears to be suddenly formed, beautiful crystals of sulphur deposited (not sublimed as by fire), and more or less sulphuric acid generated. In some places the acid was found so strong as to turn black kid gloves almost immediately to a deep red. Where the heated gas escapes in the river Pluton, such is the amount of sulphur deposited that the whole bed of the stream is made white for one or two miles below, similar to the White Sulphur Spring in Virginia. From numerous experiments made here and in the mountains of Virginia, I am confident that all sulphur springs possess a high temperature after descending below the cold surface water. Notwithstanding that

the rocks and earth in many places are so hot as to burn your feet through the soles of your boots, there is yet no appearance of a volcano in this extraordinary spot. Were the action to cease, it would be difficult after a few years to persuade men that it ever existed. There is no appearance of lava. You find yourself standing not in a solfatara nor one of the salses described by the illustrious Humboldt. The rocks around you are rapidly dissolving under the powerful metamorphic action going on. Porphyry and jasper are transformed into a kind of potters clay. Pseudotrappean and magnesian rocks are consumed much like wood in a slow fire, and go to form sulphate of magnesia and other products. Granite is rendered so soft that you may crush it between your fingers, and cut it as easily as bread unbaked. The feldspar appears to be converted partly into alum. In the meantime, the boulders and angular fragments brought down the ravines and river by the floods, are being cemented into a firm conglomerate so that it is difficult to dislodge even a small pebble, the pebble itself sometimes breaking before the cementation yields. The thermal action on wood in this place is also highly interesting. In one mound I discovered the stump of a large tree silicified; in another a log changed to lignite or brown coal. Other fragments appeared midway between petrifaction and carbonization. In this connection, finding some drops of a very dense fluid and also highly refractive, I was led to believe that pure carbon might under such circumstances crystallize and form the diamond. Unfortunately for me however, I lost the precious. drop in attempting to secure it.

A green tree cut down and obliquely inserted in one of the conical mounds, was so changed in thirty-six hours that its species would not have been recognized except from the portion projecting outside, around which beautiful crystals of sulphur had already formed.

From the thermal exhalations and the amount of sulphur deposited, it might be supposed that the progress of vegetation. would be retarded. But such is not the fact. On the contrary it is greatly facilitated. The Quercus sempervirens or evergreen oak, flourishes in beauty within fifty feet of the boiling and angry geysers. Maples and alders from one to two feet in diameter, grow within twenty or thirty feet of the hottest steam pipes. This, however, may be accounted for by the cold surface water flowing down from the adjacent mountain. Here too the birds build their nests and "sing among the branches." Multitudes of grizzly bears make their beds on the warm grounds. Panthers, deer, hares, and squirrels, also take up their winter quarters in very midst of the geyser mounds. Farther down the stream on the terraced banks of the limpid Pluton, vegetation (as one gentlemen has aptly expressed it)" actually runs wild," and the winter months exhibit all the fancied freshness of primeval Eden.

the

I have now traced the influence of this thermal action from two to three hundred miles on the Pacific coast in California, but only in this place have I been permitted to witness its astonishing intensity. The metamorphic action going on is at this moment effecting important changes in the structure and conformation of the rocky strata. It is not stationary, but apparently moving slowly eastward in the Pluton valley.

I would respectfully invite the attention of geologists to this cause of action, which hitherto has been too little studied and at present is not perfectly understood. The investigation will probably aid in accounting for the existence of many springs independent of ordinary Artesian flow, the formation of deep and varied soils, of beds of sulphur, rock salt, chalk, clay, hydrous iron ore, gypsum, &c., and perhaps extensive sections of breccia and conglomerate like those which traverse our coutinent. California, March 17th, 1851.

ART. XVIII.—Report of Prof. ALEXANDER D. BACHE, Superintendent of the United States Coast Survey, showing the progress of that work for the year ending October, 1850. Ex. Doc., No. 12, 31st Cong., 2nd Session.

We propose to devote a short notice, such as our space will allow, to the recent Report of Prof. A. D. Bache, Superintendent of the United States Coast Survey, showing the progress state of that work, up to the latter part of 1850.

and

Our readers may be presumed to be somewhat acquainted with the nature of a work which has such an important bearing on the great interests of our country, and the advancement of science. We need, therefore, but briefly refer to the general plan and scope of the Survey.

The grand object-an accurate delineation of our coast and its adjacent waters-is pursued by a system; 1st, of primary triangulation, founded on the nice admeasurement of a base line, and embracing, wherever practicable, points of prominent interest-accompanied by astronomical and magnetic observations, for the determination of the latitude and longitude of such points, and the variation of the compass; 2nd, of more minute triangu lation, and accurate topography of the shores; and 3d, of hydrographic observations, extending to all that may help the mariner to a knowledge of the dangers or facilities of our coast navigation, in the present, and all that may point out to the government judicious modes of indicating those dangers, or increasing those facilities, in the future.

The prosecution of this primary plan allows, and is used for, the incidental promotion, not only of the discovery of phenomena and laws which may afford new helps to the general science

of navigation, but also of a worthy contribution, from our country, to the great magazines of observations which the governments and savans of the civilized world are combining to store as the treasure house of future science.

The most distinguished foreign associations and journals have expressed their attentive admiration of the work, and the hopes which they indulge of its manifold results. We cannot forbear to instance the "Bulletin de la Société de Géographie," (Paris, Jan., 1851,) which, after an extended notice, adds; "In our mention of the eminent services rendered by the Coast Survey to science and to humanity, we have indicated but a small part of the results of this admirable enterprise. Directed in all its branches with zeal and activity, it cannot fail to add each year to the consideration with which it is regarded, not only in the United States, but in every country where science and its applications to the arts of life are justly appreciated." Of the present head of the work, it says: "The new superintendent was called with unanimity to this eminent post: signalized to the esteem of his fellow-citizens by useful publications, appreciated by the principal academies of Europe, he has acquired a universal renown by services daily rendered to science, and by ameliorations of every description introduced in the various branches of the Coast Survey."

Under the system established by the present superintendent, our coast has been divided into sections (nine for the Atlantic and two on the Pacific), in all of which the work is prosecuted simultaneously and separately. The different parts of the work will thus serve, in future, to verify each other, where the triangles meet. By this plan, moreover, the resulting benefits of the survey, instead of being postponed, or partially bestowed, are distributed throughout the country, during even the first stages. of the work, in the different sections-a consideration, in its favor, of high practical moment, there being many cases, on various parts of our coast, in which even an approximation to accuracy of information is of immediate importance, to remedy the omissions or mistakes of existing charts.

The delineation of the Atlantic coast, as far south as that of North Carolina, has, in its essentials, advanced well nigh to completion; and a large number of extended and useful charts have been published. In our southern and western sections, the preliminary work is being rapidly pushed, together with, here and there, surveys in detail of important points, examined with a view to present necessities, or in compliance with special requests from the communities interested. Much valuable information, on those coasts, has indeed been already acquired and made public. Within the past year, the harbor of Beaufort, N. C., has been surveyed, and a sketch published, as also of Oregon and Hatteras inlets, which sketches have been gratuitously distributed.