ports of the officers who will have it in charge a correct appreciation of its practical usefulness can be based.

WORK ACCOMPLISHED BY THE CHALLENGER.

The thoroughness of the equipment of the Challenger, the abilities of the several officers and assistants, and the favorable circumstances generally combined to render this expedition one of the most fortunate and successful of any on record. Indeed, it may well be considered as marking an epoch in the scientific history of the world.

The first important advance made by the Challenger on our previous knowledge of the deep seas was in the discovery of a vast extent of red clay on the floor of the ocean at profound depths, and the comparative absence of life there. This extends far into the South Atlantic, merging into gray ooze to the north, while to the south a remarkable deposit of silicious matter covers the Antarctic Sea floor. The small amount of carbonate of lime and large amount of alumina and oxide of iron contained in it render its formation extremely difficult to understand. An important deduction is made that while this formation is going on to an immense extent, with but little trace of organic life in the depths below, the sea above teems with a variety of animal forms, thus having an exact analogy in well-known terrestrial strata. The cause of the absence of organic remains, as suggested by Professor Thomson, lies in the large amount of carbonicacid gas held in suspension by the sea at great depths, which acts as a solvent on the carbonate of lime, leaving only the decomposed residuum to increase the thickness of the sea bottom.

Another result of the Challenger's work has been to estab lish as general principles what was only known to exist in isolated instances, namely, the universal lowering of the temperature of the great seas with increasing depth.

Previous expeditions have shown that the fauna of the deep seas contained species, genera, and groups which existed during past ages, many of them being forms known only as fossils, thus surviving the various alterations that accom panied the geological periods. Numerous additional illustrations were found in connection with the expedition of the Challenger, which will doubtless in due time be brought forward.

In addition, however, the Challenger has shown that many of the species occur over very wide ranges in portions of the sea bottom far apart, especially those of great geological antiquity, forms being found in the New Zealand seas having a general resemblance to those at the same depth off Portugal and North Africa.

Some extremely curious forms of animal life were obtained by the Challenger, among them one crab that appeared to be all eyes, and another without any. The two remarkable sea-urchins obtained in the Porcupine expedition, Salenia and Pourtalesia, were found by the Challenger, the latter over a wide area. A great hydroid was found, as large as a young tree, and many sponges of exquisite beauty. The globigerina, under the careful examination of surface specimens, proved to have a spiny coat surrounding the holes, through which the contractile and motile yet structureless protoplasm protrudes.

The deepest Atlantic sounding was made nearly ninety miles north of St. Thomas, in 3875 fathoms; the deepest in the Pacific was about five degrees east of Jeddo, 3950 fathoms, with a bottom of red clay. In the Pacific there were some very important observations made in regard to the existence of confined basins at the sea bottom, having a uniform temperature for a considerable depth. The depth of these submarine basins was ascertained by noting the distance over which the same temperature was maintained. When the thermometer indicated a gradual lowering of temperature to a certain point, and then remained unchanged with increasing depth, it was concluded, with great show of reason, that the area was surrounded by a barrier without any opening through which the bottom waters could peneNo such basins were found in the Atlantic.—13 A, June 3, 1876, 538.

trate.

SWEDISH ARCTIC EXPLORATIONS TO 1875.

The Swedish government publishes in a small pamphlet a general account of Sweden, and a catalogue of the objects presented by the Swedish government for exhibition in the International Geographical Congress at Paris in 1875. In this volume we find noticed the following Swedish expeditions for the exploration of the arctic regions: In 1837

L

Professor Sven Loven began an expedition to Spitzbergen which continued until 1838, in which year the French gov ernment sent out a similar expedition, generally known as the Commission du Nord. In 1857 Torell explored Iceland, and in 1858 Nordenskjöld visited Spitzbergen. In 1859 Dr. Torell explored a portion of Greenland. In 1861 a government expedition left Tromsö for Spitzbergen, Dr. Torell being chief, with Nordenskjöld and others as his collabora tors. In 1863 Dr. Quennerstadt undertook an expedition to the island of Jan-Mayen and the neighboring seas. In 1864 a third Swedish expedition was sent to Spitzbergen, Dr. Nordenskjöld being chief of the scientific corps. In 1865 Dr. Paijkull explored Iceland. In 1868 a fourth Swedish expedition was made to Spitzbergen, under the direction of Nordenskjöld and a considerable corps of scientists, in which expedition Beeren Island was visited. In 1870 Dr. Nordenskjöld undertook a voyage to Greenland, hoping to make use of Esquimau dogs for sledge journeys. The principal field of their explorations was the west coast of Greenland, between the 68th and 71st degrees of latitude. This expedition was very successful in the collection of large masses of meteoric iron. In the spring of 1871 an expedition to Greenland was made by a vessel of the Swedish Navy, under the command of Baron Von Otter. In 1872 an expedition intended to pass the winter at Spitzbergen was sent out, consisting of three vessels, under Palander and Crazensteon; and two other Swedish expeditions were also sent to Spitzbergen under private expense-one in 1870, with the object of exploring the phosphatic strata. The second expe dition of 1872 was also urged in the same interest, but accomplished much for geology. Finally, the expedition of 1875 to Nova Zembla was carried out entirely at the expense of Oscar Dickson. It was under the scientific direction of the indefatigable Professor Nordenskjöld.

EXPLORATIONS MADE UNDER THE DIRECTION OF F. V.

HAYDEN IN 1876.

For reasons beyond the control of the geologist in charge, the various parties comprising the United States Geological and Geographical Survey of the Territories did not commence their field work until August. Owing to Indian hos

tility, the labors of the Survey were confined to the completion of the Atlas of Colorado. Therefore the work of the season of 1876 was devoted to finishing the entire mountainous portion of Colorado, with a belt fifteen miles in width of Northern New Mexico, and a belt twenty-five miles in breadth of Eastern Utah. Six sheets of the Physical Atlas are now nearly ready to be issued from the press. Each sheet embraces an area of over 11,500 square miles, or a total of 70,000 square miles. The maps are constructed on a scale of four miles to one inch, with contours of 200 feet, which will form the basis on which will be represented the geol

The point of departure the past season was Cheyenne, Wyoming Territory.

The primary Triangulation party was placed in charge of A. D. Wilson, and took the field from Trinidad, the southern terminus of the Denver and Rio Grande Railway, August 18th, making the first station on Fisher's Peak. From this point the party marched by the valley of the Purgatoire, crossed the Sangre de Christo Range by way of Costillia Pass, and followed the west base of the range northward as far as Fort Garland, making a station on Culebra Peak. About six miles north of Fort Garland is located one of the highest and most rugged mountain-peaks in the West, called Blanca Peak, the principal summit of the Sierra Blanca group. On the morning of August 28th the party started to ascend this peak. They found no difficulty in riding to timber line, which is here about 12,000 feet above sea-level. Here they were compelled to leave the animals, and carry the instru ments themselves. The main summit is about two miles north of the first point, in a straight line, and connected with it by a very sharp ridge, difficult to pass on account of the loose rocks and the constant fear of tumbling. After difficult climbing they found themselves on the summit. From here a magnificent view was spread out before them. A large portion of Colorado and New Mexico could be seen. This point is the highest in the Sierra Blanca group, and, as far as is known at the present time, is the highest in Colorado. The elevation was determined by Mr. Wilson. First a mean of eight barometric readings, taken synchronously with those at Fort Garland, gave a difference between the

two points of 6466 feet; secondly by fore and back angles of elevation and depression, which gave a difference of 6468 feet. The elevation at the Fort was determined by a series of readings compared with the Signal Service barometer at Colorado Springs, giving an elevation of 7997 feet, making Blanca Peak 14,464 feet above sea-level. This peak may be regarded therefore as one of the highest in the United States. A comparison with some of the first-class peaks in Colorado will show the relative height:

above sea-level...

Feet.

Blanca Peak

14,464

The foregoing table will afford some conception of the dif ficulty encountered in determining the highest peak, when so many occur that are nearly of the same elevation. About fifty peaks are found within the limits of Colorado that exceed 14,000 feet above sea-level.

From this point the party proceeded westward across the San Luis Valley and up the Rio Grande to its source. From the head of the Rio Grande the party crossed the continental divide, striking the Animas Park, thence by trail to Parrott City.

After making a station on La Plata Peak, the party marched northwest across the broken Mésa country west of the Dolores, making three stations on the route. After making a primary station on the highest point of the Abajo Mountains, the party turned westward to Lone Cone; thence crossing the Gunnison and Grand Rivers, they proceeded to the great volcanic plateau at the head of the White River. The final station was made between the White and Yampah Rivers in the northwestern corner of Colorado. During this brief season Mr. Wilson finished about 1000 miles of topog raphy and made eleven geodetic stations, thus connecting the whole of Southern and Western Colorado.

In company with the Triangulation party, Mr. Holmes made a hurried trip through Colorado, touching also portions of