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again, may be judged from the fact that it fills the ancient valley of the Sill, and that the modern river had to cut down through more than 300 feet of it before coming to the underlying rock, into which the river bed has now worn its way to some depth. As the road winds along the face of the steep slope of the clay gorge, it affords a view of the railway on the opposite side far below, cut in the hard rocks close to the river, while the slope above is so unstable that it remains in many places bare of vegetation, and wattled fences have been run along in zigzags to bind the clay and reduce the risk of damage to the roadway by sudden falls. In the moraine material the action of sub-aërial denudation has produced a number of " fairy chimneys,” the Erdpyramiden, or earth-pillars, with which the name of Tyrol is usually associated in elementary text-books of geology; but they are neither so large nor so picturesque as those of the Finsterbach, the view of which so well repays the labor of the arduous climb from Botzen to the Ritten plateau.
Two nights were spent at Innsbruck, and the whole of Friday the 21st was devoted to the study of the sections along the mountain slope of the left side of the Inn. Here the interglacial deposits were seen in their most impressive form. A steep climb along a clay slope of unquestionable moraine, crowded with highly polished and striated pebbles, showed an overhanging cornice of compact breccia resting on the moraine, and itself a hardened water-bedded deposit. Mayr's great quarry in this reddish breccia is a prominent object as seen from Innsbruck, and has supplied a great part of the stone which, from its hardness and durability, causes the newer streets of that town to recall the clear-cut buildings of Aberdeen. Above Mayr's quarry comes a nearly level plateau—the top of the terrace of accumulation—1000 feet above the flat floor of the valley, and similar in its features to the terrace of the Wippthal, through which the Sill cuts its way, as seen from Schönberg. As the quarry is carried farther back the loose material above the hard breccia is cleared away in advance, and so a series of excellent sections of the upper moraine is exposed. The intercalation of this mass of breccia, several hundred feet thick, is a proof of the comparatively long duration of the interglacial period in which, according to Penck, it was formed as a talus or scree on the shores of the ancient Inn lake.
The remarkable terrace which breaks the steep slope of the mountains on both sides of the Inn valley is only found between the letzthal and the Zillerthal, from each of which glacial accumulations had blocked the main valley, thus giving origin to a lake which, invading the lower Wippthall also,
allowed the interglacial deposits to form on its margins, which are now represented by the top of the lateral terrace.
From Innsbruck the excursion proceeded by rail along the Inn valley into Bavaria, then by a branch line across the glacial amphitheater of the Inn, and the monotonous plain south of Munich to Deisenhofen, whence the Isar was reached on foot. The contrast of the uniform levels and low moraine hills of this northern slope, with their ranges of rather dwarfish pines in monotonous plantations, was sharp when compared with the more abrupt slopes and richer vegetation of the southern side. The true plateau character of this country appeared when, after a walk of several miles along a straight and absolutely level road, a break in the line of trees in front showed the swift Isar flowing almost at our feet, and a steep path descending the gorge to its shore. Crossing the river we reached Höllriegelskreut, and saw a succession of sections demonstrating the triple glaciation and intermediate genial periods. Next day a trip was made from Munich to the Würmsee, or Lake of Starnberg; but the weather proved so unfavorable that, for the first time on the excursion, the full programme for the day as planned by the leaders could not be carried out. It was possible, however, to visit a remarkable surface of interglacial conglomerate at Berg, which has been enclosed and placed under cover by the German and Austrian Alpine Club, a body which has rendered inestimable services to the scientific visitor, as well as the tourist and climber, along the whole line of the Eastern Alps. This surface is so strongly glaciated that the rock is polished as if by a lapidary, and the internal structure of every constituent pebble is clearly seen. The characteristic striæ are there, showing how the glacier, long since shrunk back to the obscurity of the central Alpine ridge, had advanced over the hardened mass of cemented pebbles sorted out by water from an earlier moraine, and cut by its intense erosive power through pebbles and matrix alike. The Würmsee is deeper below the general level of the plain than the surrounding hills are high above the surface, and it is entirely surrounded by the interglacial deposits known as Deckenschotter, in which it seems probable that the whole basin was eroded beneath the pressure of the last great ice sheet.
In concluding this short account of a delightful and memorable excursion, it may be of advantage to define the nomenclature and summarize the general theoretical conclusions arrived at by Drs. Penck, Brückner, and Du Pasquier.
Glacial deposits, so far as they occur in the Alps, are divided into two classes—the glacial, or moraines properly so called ; and the fluvio-glacial, or alluvia formed by the action of running water on moraines. The latter are usually clearly strati. fied, but contain many pebbles marked by glacial striæ. Fluvio-glacial deposits are always being formed on the outer slopes of moraines, forming a gentle slope leading from the edge of the morainic amphitheater to the plain of the enclosed depression. A complex of glacial and fluvio-glacial deposits of contemporaneous origin corresponds to each phase of the cessation of glaciation. Thus in a single glacial series there may be a succession of complexes, one partially superimposed on another, and each corresponding to a definite stage of retreat or advance of the ice. The fluvio-glacial deposits in a single glaciation are spoken of as inter-stadiary.
Under the deposits of relatively recent glacial accumulation which are characterized by trifling superficial alteration due to weathering, two other glacial series are found distinguished from each other and from the most recent series by highly weathered layers or by evidence of great erosion, showing the existence of a long sub-aërial period between each epoch of glaciation. These periods are termed interglacial in distinction to the brief interstadiary periods which occur in the course of a single glaciation. Amongst the interglacial deposits of the neighborhood of the Alps, at least on the north of the chain, loess must be included. Lehm is a product of alteration of loess, mainly distinguished by the absence of carbonate of lime.
The more ancient moraines are often weathered externally into a brick red crust, termed ferretto by the Italian geologists. The moraines so coated always occupy the outer side of morainic amphitheaters, and are therefore called external moraines in distinction to the more internal moraines, which form the inner slopes and in part rest upon the more ancient. This is not a mere case of superposition, but of actual enclosure, the external moraine extending around as well as partially under the internal. The alluvia of the most ancient glaciation are termed plateau alluvia (Deckenschotter), those of the intermediate glaciation high-terrace alluvia (Hochterrassenschotter), and those of the most recent stage low-terrace alluvia (Niederterrassenschotter).
I cannot conclude without an expression of gratitude to Professor Penck, for his great kindness and tireless patience in not only showing, but making sure that every member of the excursion saw and understood, the various features which he explained.
ART. XIII.—Distribution of the Echinoderms of North
eastern America ;* by A. E. VERRILL. (Brief Contributions to Zoology from the Museum of Yale College, No. LVIII.)
ABOUT 200 species of Echinoderms are now known from the Atlantic Ocean, adjacent to the North American coast, north of Cape Hatteras. Of these, over 100 species have been discovered in recent years, since the deep sea dredgings were undertaken. The “ Challenger," 1873; the “ Blake," 1880 ; the “ Fishhawk," 1880-1882, and the “ Albatross,” 1883–1887, each brought to light many new forms. Those dredged by the “ Challenger” were, however, not described until 1889. Those collected by the two steamers last named, as well as several derived from previous explorations, were mostly described by me, from 1878 to 1885. Many of these necessarily brief descriptions appeared in this Journal, from time to time, in this series of “Brief Contributions to Zoology."" It seems desirable, therefore, to bring together here all the species, with a brief review of their distribution, as known at present. Of the 200 species now recognized, about 137 may be classed as deep-water species, as they rarely if ever occur in less than 50 fathoms. About 116 species are found in depths greater than 500 fathoms. Many of these have a wide range in bathymetrical distribution, some of them ranging from less than 100, to more than 1000 fathoms. The same is true of some of the shallow water species. About 58 species have been found to occur only at depths greater than 500 fathoms; these may be classed as true abyssal species. Many of our species also have a wide geographical range. A considerable number occur on the eastern side of the Atlantic and in the Arctic Ocean. Several extend southward to the West Indies, and some even to the Indian and Pacific Oceans.
More complete details in regard to the distribution will be given in connection with the general lists of each class. The general distribution in depth may be illustrated by the following table :
* Abstract of a paper read before the National Academy of Science, Dec. 31, 1894.
Especially in Nos. 38, 39, 42, 49, 50, 51, 55, 56, 57. Other species were described by me in the Proc. U, S. Nat. Museum, vol. ii, p. 165, 1879; vol. viii, p. 423, 1885; and in vol. xvii, pp. 245-297, 1891.
Many were figured and described, in . Results of the Explorations made by the steamer Albatross, in 1883," in the 11th Annual Report of the Commissioner of Fish and Fisheries, 1885.
In this article the localities indicated by station numbers and by latitude and longitude, unless otherwise stated, are those of the United States Fish Commission,
Bathymetrical Distribution of N. E. American Echinoderms.
37 20 2 12 12 83
10 11 73 1000-2000 22
1 12 13 74 2000–2600
0 It will be seen from the above table that the species of Echinoderms are more numerous between 100 and 500 fathoms than in any other zone of depth. It is also in this zone that many species occur in the greatest abundance of individuals. This is largely due to the fact that off much of our coast, a profuse fauna is sustained at those depths by the direct influence of the Gulf Stream, as shown in several of my former articles.
A brief statement of some of the results and conclusions, arrived at from the study of this group, may be given here, leaving a more detailed discussion of the subject for another occasion.
1. The abyssal genera and families are mostly very widely diffused over the three great ocean basins.
2. The species belonging to abyssal genera are usually restricted in range to particular regions or to a single ocean.
3. Those genera and species having the greatest bathymetrical range are also generally the most widely distributed geographically. Some of these species range from very shallow water to 1000 fathoms or more, and may extend geographically into all the great oceans.
4. Some of those species belonging to the intermediate depths (100 to 500 fath.), known as the “continental zone," often have a very wide geographical range. Many of them extend to European waters, and some even to the Pacific.
5. Many of the most peculiar and remarkable new genera belong to the continental zone, or even between 50 and 200 fathoms.
6. Many peculiar and conspicuous genera and several remarkable families are nearly or quite contined to the abyssal zone.
7. Abyssal genera are often endowed with special structures adapted to the peculiar physical and biological conditions in which they live, especially to the food upon which they feed and to the soft mud or ooze in which most of them live more or less buried.
8. The abyssal species in many cases appear to be capable only of very slow dispersion, as compared with shallow water species. This is, at least in many cases, due to the fact that