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The whole number of fishes he had collected from Lake Superior was 33, about a dozen of which were entirely new varieties.

Prof. Agassiz then read Prof. J. W. BAILEY's paper “ON MICROSCOPIC FORAMINIFERA, FROM THE SOUNDINGS OF THE COAST SURVEY,” to decide whether of importance in navigation. He spoke of the figures given, as valuable from being given as seen, and not drawn with any attempt to give them with precision, as supposed to exist.

Dr. S. G. MORTON submitted the following letter from Prof. M. TUOMEY on the results of his observations in the Tertiary region of South Carolina.

Alabama, Sept. 5, 1848. Dear Sir,--I sent you, some days since, as I once promised, a specimen of A. placenta and T. thoracica, from the Eocene of Wilmington, N. C. Of the former species I think there is doubt, the latter I must leave to you. You may recollect, that on another occasion I sent P. Gregale and T. Harlani from S. C. I intended to have accompanied the specimens with a paper on the Eocene of N. and S. Carolina, but as my report on the geology of the latter State will soon be published, I have thought it better to postpone it for the present, particularly as I am on the way towards St. Stephens, to examine the orbitoidal limestone of that place.

Should this reach you in time, may I ask the favour of you to state to the Geological Secretary of the Association of Geologists, the following results of my investigations in the Tertiary of South Carolina, provided that you find them of sufficient interest.

1st. That the Eocene of S. Carolina is composed of three well characterized divisions : of these, the lowest in the series is the burrstone formation, consisting of beds of sand, clay, gravel and grit, resting upon the cretaceous beds.

The fossils, which are all silicified, occur in the upper part of the formation, and along the verge of the superincumbent calcareous strata ; they are for the most part identical with those of Claiborne, and represent a littoral fauna. The Santee beds, which overlie the burrstone, consist of limestone, marl and green sand, being an extension of the Eocene of Wilmington. These are again overlaid by the marls of the Ashley and Cooper rivers.

2d. Although the fossils of these beds include nearly all of those considered characteristic of the Eocene of the United States ; never

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theless, there are among them well characterized cretaceous forms,* such as

Ammonites placenta, De Kay, Loc., Wilmington, N. Carolina.
Trigonia thoracica, Morton, ,
Terebratula Harlani,

Santee, S. Carolina.
Plagiostoma gregale,
Ostrea panda,
Gryphæa mutabilis,

3d. That the fossils of the Middle Tertiary of S. Carolina contain 46 per cent. of recent species ; I have therefore referred that formation to Mr. Lyell's Older Pliocene. The proportion of recent species seems to increase from north to south.

4th. That the Post Pliocene contains several forms no longer found living on the coast of the State, but belong to the living fauna of Florida and the West Indies.

5th. That the coast of S. Carolina presents no evidence of very recent subsidence, as stated by some visiters; but that all the phenomena attributed to that cause are the result of the horizontal changes going on at this moment. I am, dear sir, with sincere respect,

Yours, &c.

M. TUOMEY.

Afternoon Session.

In addition to the officers chosen for this Section, Dr. A. A. GOULD was appointed an additional Secretary, and Prof. SAMUEL HENRY DICKSON and Prof. J. Hall were added to the Standing Committee which now consists of the following members :

Prof. L. AGASSIZ, Chairman ; Dr. R. W. GIBBES, Secretary ; Dr. A. A. GOULD, Assistant Secretary ; Prof. S. H. Dickson and Prof. J. HALL.

The Section then proceeded to business. Several specimens of the tracks of Mollusca upon sandstone were exhibited by Prof. HALL, who gave his views upon them, as evidences of beaches in the Silurian period. From these tracks of the Mollusca, he was led to believe that sea beaches formerly existed far in the interior of the land. He also exhibited and described some fossils from the Onondaga salt group.

* Mr. Lyell admits 0. cretacia among the fossils of the orbitoidal limestone of Alabama.

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Dr. LECONTE expressed his views “On the Geographical Distribution of Coleoptera," which will be published at length in a work now in preparation for the press.

After an animated discussion on the subject of the geographical distribution of animals, in which many members took part, it was moved and seconded, that an election be held for Chairman, when Dr. S. G. MORTON was unanimously chosen.

The Section then adjourned to meet to-morrow at 10 o'clock, A. M.

R. W. GIBBES, Secry.

September 21.
SECTION OF GENERAL PHYSICS, &c.

Morning Session. Pursuant to the order of business, the Section for General Physics met at 10, A. M., in the Chemical Hall of the University.

A programme of business was submitted by the Committee, and the first page read was

A REPORT ON THE WINDS OF THE NORTHERN HEMISPHERE.

BY PROF. J. H. COFFIN.

.

After some remarks upon the importance in investigations of that kind, of lengthened periods of observation, for the purpose of eliminating accidental errors, and of extending the field of research over as wide a field as possible, he proceeded to classify the observations which formed the basis of the report according to the regions or countries in which they were taken. These were widely scattered over both continents, and the Atlantic, Pacific and Arctic Oceans, and embraced an aggregate period of over two thousand years, at 550 fixed stations, beside numerous voyages and tours. A more extensive collection, he remarked, than had ever before been brought together for the purpose.

He next proceeded to point out the method he adopted to determine from these observations, the mean course of the wind, which was the same as that by which the traverse of a ship at sea is resolved.

By the aid of extensive diagrams, he then proceeded to establish the fact that between lat. 33° and 60°, there is a general current

from the west (or rather from a little to the south of west) extending entirely round the globe; but that, as we approach those limits, (particularly on the south), it gradually loses its decided character, and at the limit all trace of a fixed direction disappears, the current at any place being controlled entirely by local influences. This he illustrated by a separate diagram of the winds at Augusta, Geo. After passing this limit, on the south, he showed that a current from the opposite direction sets in, which, as we go south, gradually assumes a more decided character till we come fully within the limits of the trade-winds. He alluded, in passing, to a peculiarity in the winds west of the Mississippi, between lat. 30° and 40°, as explaining the tracks of storms in those regions.

North of lat. 60°, he showed that there are indications that the strong current that comes down from the north, in the polar regions, veers toward the west, thus establishing a third system, which breaks up at about lat. 60°.

The observations taken at various places, in Russian and British America, Norway and St. Petersburg, in Russia, were alluded to as indicating this fact.

After having gone through with his remarks upon the general course of the winds, he took up the subject of the annual curve which they describe, and showed that while on the eastern coast of Asia it is the same as here, in Europe the curvature seems to be in the opposite direction. Also, that a curvature, physically similar, exists in both the easterly and westerly systems of winds.

He next spoke of the relative force of the different winds, showing how far the general results are modified from this cause.

After remarking that he was compelled, for want of time, to omit several matters embraced in the report, he closed with an expression of thanks to the numerous friends who had aided him in obtaining the necessary data, and whom he mentioned by name, with the kind of aid received from each.

The next subject was A DISCOURSE ON THE FLEXIBLE SURFACE. BY PROF. B. PEIRCE. [Not received.]

Prof. C. U. SHEPHARD, through Prof. B. SILLIMAN, Jr., presented a “REPORT ON METEORITES,” which has been published in the American Journal of Science and Arts, November, 1848, p. 402.

A paper was now read

ON THE VOLATILITY OF POTASSA AND SODA, AND THEIR CARBONATES.

BY PROFS. W. B. ROGERS AND R. E. ROGERS. This communication detailed the results of numerous experiments, proving that these materials have a much higher volatility than has hitherto been recognised by chemists, and exhibiting the comparative rapidity with which they evaporate when exposed to the heat of the alcohol lamp and that of the blowpipe.

When potassa, soda, magnesia and lime, were similarly heated and weighed, from time to time during the process, it was found that potassa was most volatile; soda came next, magnesia was much less volatile than soda; and lime so greatly inferior, in this respect, to magnesia, as to require a long continued high temperature to cause a sensible loss. The carbonates of potassa and soda presented the same order, and nearly the same degree of volatility as the bases themselves.

Two separate modes of experiment were adopted. In the one, the substance in solution was dropped in small quantities, on a slip of platina foil, so as when dried to form a delicate tache on the metallic surface. This tache was subjected to the heat of a spirit lamp, by holding the foil in the flame, or again to the stronger heat of this flame, urged by the mouth blowpipe. The change in the tache, in each case, was tested by its alkaline reaction, on delicately prepared turmeric paper.

The second method, a weighed quantity of the alkali, or other material, was exposed to the strongest heat of the table blowpipe, and the evaporation marked by weighing at stated intervals. The following extracts, from the register of experiments, will exemplify these methods and their results.

I. Experiments with the Tache. The tache, in each case, was formed from one, two or more drops of the particular solution used ; so that all the taches in each series were exactly equal.

1. Taché of Potassa on platinum foil having a strong alkaline reac

tion, heated by the mouth blowpipe for 2", was entirely dissipated. Its place on the metal presented no trace of alkaline reaction. By repeated trials it was found that at this heat a

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