terms; and there are now engaged, in all parts of the ocean, hundreds of vessels making and recording observations for this work. Never, before, was such a corps of observers known; and never, before, could the commercial marine of any country boast of such a body of navigators as are those of America.

The importance of simultaneous observations, in all parts of the ocean, cannot be overrated. They would enhance the interest of the work, and greatly add to the value of the results. The field is as wide as the ocean, and there is room in it yet for multitudes of labourers, thousands of whom are wanted for simultaneous observations. The work is not exclusively for the benefit of any nation or age; and, in this view of the subject, it was suggested, whether the states of Christendom might not be induced to co-operate with their navies in the undertaking; at least so far as to cause abstracts of their log-books and sea-journals to be furnished to Lieut. MAURY, at the National Observatory, Washington.

A communication was received from Dr. Hare, inviting the members to a conversazione at his house on Monday evening next, which was, on motion, accepted.

Prof. W. B. ROGERS offered the following resolution :-
:-

Resolved, That a Committee of five be appointed to address a memorial to the Secretary of the Navy, requesting his further aid in procuring for Lieut. MAURY the use of the observations of European and other foreign navigators, for the extension and perfecting of his charts of winds and currents; which resolution was adopted, and the following appointed said committee, viz. Prof. W. B. ROGERS, of Virginia, Prof. JOSEPH HENRY, of Washington, Prof. B. PEIRCE, of Cambridge, Mass., Prof. JAMES H. COFFIN, of Easton, Pa., and Prof. STEPHEN Alexander, of Princeton N..J.

On motion of Prof. Agassiz, seconded by Prof. W. B. ROGERS, Resolved, That the thanks of the Association be tendered to the Committee on the Sediments of the Mississippi river, for the report this day rendered to the Geological Section, and for the able and satisfactory manner in which the duties of said Committee have been performed.

Resolved, That it is highly desirable that immediate steps be taken to publish entire the series of valuable observations and important deductions made by the above Committee.

On motion adjourned, to meet at half past 7 o'clock this evening, at which time it was announced that the annual address by the Chair

man of the last annual meeting would be delivered, and that communications would be made by Prof. B. PEIRCE and Prof. L. AGASSIZ.

Friday, Sept. 22, Evening general and public Session. The Association met agreeably to adjournment, President WILLIAM C. REDField, Esq., in the chair.

The President announced the annual address, when Prof. Wм. B. ROGERS rose and delivered an extremely interesting and spirited discourse, which we regret that ill health has prevented his writing out for publication.

Prof. BENJAMIN PEIRCE next read a paper "ON THE GENERAL PRINCIPLES OF ANALYTICAL MECHANICS." [Not received.]

Prof. LOUIS AGASSIZ followed with a paper "ON THE CLASSIFICATION OF THE ANIMAL KINGDOM." [Not received.]

The Association then adjourned to meet to-morrow morning at 4 o'clock, P. M., in the Chemical Lecture Room of the University. WALTER R. JOHNSON, Sec'ry.

September 23.

SECTION OF NATURAL HISTORY, GEOLOGY, &c. Third Meeting.

At the meeting this morning Prof. W. B. ROGERS was called to the chair.

Prof. AGASSIZ then proceeded to give his views upon

THE TERRACES AND ANCIENT RIVER BARS, DRIFT, BOULDERS, AND POLISHED SURFACES OF LAKE SUPERIOR.

He said that the remarks he was about to present upon this subject were more of a practical kind than made in reference to the theory which he thought likely to explain these phenomena. He would insist upon the facts, in order, if possible, to arrive at just conclusions. The hypothesis he presented was derived from an investigation of the Swiss glaciers. He went on to explain the identity of these phenomena with the appearance of those regions where the glaciers occur.

It was his conviction that two distinct causes had produced these

appearances upon Lake Superior. He had observed evidences of the action of water, but there were other phenomena for which he claimed another agency, viz. the terraces around the lake; which he believed indicated the shores of former water basins, showing different levels of the lake-some of these being at its present margin, others higher and higher-giving evidence of former elevated stages of the water. Hence he had little doubt, that the relative level between dry land and water had changed, to the amount now existing between the highest terrace, and the margin of the lake, which is some three hundred feet. He here illustrated his position by the black-board. He thought they presented evidences of paroxysms. Let me, he said, give a few illustrations.

He then proceeded to represent, by diagrams, successive gradations of cliffs and beaches, until we come to the present actual margin of the lake, showing that the lower basin was formed by the action of water upon the earlier deposits of matter. It is now a question whether these changes of level have been produced by a subsidence of the water, or an upheaval of the land. Facts have been brought forward to show that the water has sunk, but Professor A. inclined to the theory, that the land has risen, caused by a paroxysm or upheaval. It would be difficult, he thought, to account for the action of the water, in producing these basins, three hundred feet above the level of the lake, if there had been no change in the formation of the land. If the water had had a free outlet, as now, through the Sault St. Marie, he did not see how it was possible for the water to have risen so high as the summit of the highest of these beaches. Hence, he leaned to the geological theory of the upheaval of the land.

There was another point to which he wished to refer the appearance of the muddy drifts and polished surfaces of the lake. He could not see that the polished surfaces were owing to the action of water, for it is characteristic of the action of that element, on a great extent of land, to groove or channel out all the softer portions, by which means, the harder portions of the veins were left projecting. But here, all were ground down equally to one uniform level.

We have scratches upon this surface, indicating pressure from above, and it was his impression, that these phenomena of the North have been produced by causes identical with those which have produced the glaciers. If we can find whether these glaciers move always in an inclined plane, or by some other cause, we shall have settled a great point.

Professor A. then went on to define the climatic differences which

occur in different regions of our own and other countries, with the alternate changes of freezing and melting-or larger and smaller masses of water; and these changes he thought would be sufficient to move any masses of snow and ice over the flattest surface-even over hills and mountains, if the mass possessed sufficient momentum.

Now where do we observe these scratched and polished surfaces? On the tops of mountains, and the highest hills; yes, on their very summits. He then attributed these effects to the agency of icealthough, to a great extent, there are other phenomena which must arise from the action of water.

Prof. AGASSIZ also made remarks upon

THE BLACK BANDED CYPRINIDE.

He observed that the markings (the black bands), usually considered so characteristic of the species, go for nothing, when we find that these bands are only observable in the young, and that they are gradually obliterated.

He next proceeded to say, that it was necessary to separate from the family of Cyprinidæ, those which he denominated Cyprinodonts. He illustrated his meaning by the black-board. The difference was -that the former had an additional tubercle behind the cerebellum ; but in the Cyprinodonts, we have a simple brain without the tubercle.

The next subject was a few observations by Prof. AGASSIZ, on the

MONOGRAPH OF GARPIKES.

He said, it would be recollected, that in the Pliocene, or New Red Sandstone of Connecticut, great numbers of fossils have been found, in various stages of preservation. He had thought it expedient to examine monographically the present existing species of fishes, which closely resemble these fossils. The only types living, which bear a particular resemblance, are the Garpikes. These have been distinguished by several different species, but he had divided the genus Lepidosteus (the Garpikes,) into two types-the sharpnosed and the flat-nosed. Yet he thought he had found three species, in this investigation, of the former, and also two or three of the latter, or flat-nosed. The details of these investigations, he continued,

would be of very little interest. He hoped, however, that they would soon be sufficiently developed to bring the attention of paleontologists to bear upon the subject. He referred to the structure of the Crinoids-that is, those star fishes which, in their earlier stages of life, rest upon a stem. He demonstrated his meaning by the black-board. The star fishes, he said, when full grown, show apparently a quite different animal, caused by the formation of loose plates, arranged variously on the surface, and we notice a calcareous centre, whence the different rays diverge. The only difference discoverable was, that instead of these plates forming a series of loose particles (as in the young,) they are united, in the full-grown animal, into hard developed rays, and the creature assumes its permanent form of a single star, instead of its former branched appearance.

Dr. R. W. GIBBES next presented a remarkable fossil, which he desired to refer to Prof. AGASSIZ for examination. Prof. A. being thus called upon, said he thought it extremely interesting, and that it seemed to bear a close resemblance to the great group of cartilaginous fishes, and thought it likely to indicate a new family, intermediate between the Saw fish (Pristis) and the Cestracionts. The locality, in the far west, is not certainly known, but it is most likely from the cretaceous.

Mr. T. GREEN exhibited and described some new forms of Rhamnus lanceolatus.

66

Prof. HUNT read a paper "ON ACID SPRINGS AND GYPSUM DEPOsits of the Onondaga Salt GROUP," which has been published in the American Journal of Science and Arts, March, 1849, p. 175. Prof. J. C. BoотH next presented a paper

ON THE PHYSICAL GEOGRAPHY AND GEOLOGY OF THE NORTHERN PORTION OF THE STATE OF MISSISSIPPI. BY RICHARD BOLTON, Esq.

The region between the Mississippi bottom and the Tombigbee valley, presents ranges of hills of nearly uniform height, from 80 to 150 feet above the adjacent water-courses, the principal streams being about 18 miles apart. It may, therefore, be regarded as nearly level land, denuded by these water-courses. The water-courses have an upper or dry bottom; a lower wet bottom, subject to overflow in winter, and heavily timbered, and are usually from 1 to 200 feet wide. The valleys and broader hill-tops offer rich arable land to the