of Switzerland distinct, and the materials in well-determined order, 396. Similar phenomena observed in other parts of Europe, 396-7.— Points necessary to be settled; first, the relation in time and character, between the Northern and the Alpine erratics, 397.-Traced in North America, 397-8.-Not yet settled whether any local centres of distribu- tion in this country; but the general cause must have acted in all parts simultaneously, 398.-The action ceased at 35° north latitude; this incompatible with the notion of currents, 399.-In both hemispheres a direct reference to the polar regions, 400.-Difficulty as to so extensive formation of ice, removed; difficulties on the theory of currents, the effects contrary to experience of water-action, 401.-Erratic phenomena of Lake Superior, 401-4.-The iceberg theory, 405-6.-Description of appearances at Lake Superior, 406-9.-Drift; contains mud, and is without fossils, 409.-Example of juxtaposition of stratified and un- stratified drift, at Cambridge, 410.-Date of these phenonema not fully determined, but doubtless simultaneous all over the globe, 410-411.- The various periods and kinds of drift distinguished, 412.-Accompanied by change of level in the continent; terraces at Lake Superior, 413-14.- Not from a subsidence of the water, but from upheaval of the land, 395-416 The present physical state of our globe the result of gradual and suc- cessive changes, 417.-Necessity of studying out in detail minor and secondary phenomena, 418.-Position and general features of the Great Lakes, 419-20.-Lake Superior; the dykes correspond in direction with the trend of the shores, 420.-Details, 421-2.-Enumeration of the various systems of dykes, 423-4.-These dykes have cut up the primi- tive formations so as to produce the present outlines of the lake, 424-5. -The rocks of Lake Superior as evidence that the erratics of more southern localities were derived from the primitive range extending 4. GASTEROSTEUS PYGMEUS; G. NEBULOSUS; BOLEOSOMA MACULATUM ; ETHE OSTOMA ZEBRA...... ..305 5. ACIPENSER CARBONARIUS....... ..271 6. HYLODES MACULATUS; RANA NIGRICANS; AND A CROTALOPHORUS.. ....378 ..387 ..239 9. THE OUTLINES OF LAKE SUPERIOR, showing the several systems of dykes, and the direction of the glacial scratches in various localities..... .417 ERRATA. Page 10, Note, for Tocelyn read Jocelyn. Page 31, for Sault to Michipicotin read Sault to Fort William. Page 58, for Juniperus Virginianus read J. virginiana. Page 384, first line of list, the specific names cedrorum and cacalotl should exchange places. STANFORD LIBRARY LAKE SUPERIOR. NARRATIVE. CHAPTER I. BOSTON TO THE SAULT DE ST. MARIE. WE left Boston on the 15th of June, 1848, at 8 A. M., in the cars for Albany. The weather was warm, and we were well powdered with dust, when, at about 6 P.M., we arrived at the ferry on the Hudson. The Western appears to be more exposed to this nuisance of dust than the other railroads, probably from the many cuts through banks of crumbling clay and gravel. We were interested to hear that a contrivance for watering the track had been proposed and successfully experimented on. At the hotel we found the New York members of our party, which now numbered eighteen. After tea we assembled in a large room up stairs, where Prof. Agassiz made the following remarks on the region over which we had passed :— : "The soil of this tract is of great variety, but everywhere presents this feature that its surface is covered with loose materials, all erratic, (or belonging to rocks whose natural position is distant from the points where these fragments are found,) and all evidently transported at a very remote epoch. These erratics are of all sizes, from sand to large rocks; the larger ones angular; the smaller ones more or less rounded, scratched and polished, as are also the surfaces of the rocks on which they rest. These polished rocks have been noticeable to-day, especially to the westward of Worcester. These marks we shall find still more strongly shown as we proceed northward. "We have nowhere seen unaltered rocks, but exclusively those of a granitic character, metamorphosed from originally stratified formations by the AT action of heat. Thus, for instance, the blackish mica slate, with veins of quartz which so frequently occurs on our route of to-day-is probably clay slate, altered by intense heat, which has produced several varieties of silicate of alumina. There is no clearly defined division between these slates; they pass without interruption from baked clay into chloritic slates. In one place in the Connecticut valley we saw red sandstone, generally in a horizontal position, except where disturbed by trap. Nearer Albany we passed through a region of highly metamorphic limestone, belonging to the oldest geological deposits. We have also seen indications of the Potsdam sandstone, one of the most ancient fossiliferous rocks. "As to the vegetation, it is to be remarked in general, that the features of a country are given principally by its plants. These mark the variety of the soil, and its formation. The forests which we have seen to-day consist of a great variety of plants, mingled together. We have seen no forests composed of one species of tree. In the mountainous parts, indeed, certain species predominate, but elsewhere several are found in almost equal proportions. Among these are various pines; the white and pitch pines, the spruce, hemlock, red cedar, and a few larches. Then the Amentaceæ, viz., oaks, birches, chestnut, beech, poplar, and the platanus or button wood, (which is in a sickly condition, probably from injury done to the young wood by frosts,) hickories, elms, locust, ash, and maples, but the latter fewer in number. The hickories never form forests. About Niagara we shall find the beech abundant. Of shrubs, we have seen a great variety: e. g., sumachs of several species, (whereas in Europe there is but one,) elder, alder, cornus, viburnum, witch-hazel, willows, wild roses, and grapes. A remarkable feature of the vegetation of this country is, the number of species of grape, mostly useless for the manufacture of wine. Shrubs peculiar to America, are the Kalmias; viz., mountain-laurel and sheepsbane. In the meadows are various grassy plants, carices, and ferns; the latter in great variety. These spots exhibit probably a condition analogous to that of the Coal Period, in which the ferns, &c., prevailed. All the plants growing on the roadsides are exotics, as are also all the cultivated plants and grasses. Everywhere in the track of the white man we find European plants; the native weeds have disappeared before him like the Indian.* Even along the railroads we find few indigenous species. For example, on the railroad between Boston and Salem, although the ground is uncultivated, all the plants along the track and in the ditches are foreign. From this circum Old Tocelyn says the Indians call the common plantain (Plantago major,) “the white man's foot." |