B. range, 1137 to 1742 fath. Dredged by the U. S. Fish Comm. at three stations from N. lat. 40° 34' 18" to 39° 35'.

BRISINGA VERTICILLATA Sladen.

Brisinga verticillata Sladen, Voyage of the Challenger, vol. xxx. p. 604, pl. 109, figs. 9-11, 1889; Verrill, Proc. Nat. Mus., vol. xvii, p. 283, 1894.

B. range, 906 to 1423 fath. Dredged at 9 stations from N. lat. 41° 13' to 36° 34'. Taken by the Challenger at N. lat. 40° 17', off New Jersey, in 1350 fath.

FREYELLA ELEGANS Sladen.

Brisinga elegans Verrill, this Journal, vol. xxviii, p. 382, 1884.

Freyella bracteata Sladen, Voyage of the Challenger, vol. xxx, p. 629, pl. 114; figs. 1-4, 1889.

Freyella elegans Verrill, Proc. U. S. Nat. Mus., vol. xvii, p. 283, 1894.

B. range, 1060 to 2021 fath. Taken at 18 stations by the U. S. Fish Comm. from N. lat. 41° 43' to 36° 34'. Dredged by the Challenger at three stations from N. lat. 42° 08′ to 40° 17', in 1250 to 1350 fath., off the American coast.

FREYELLA MICROSPINA Verrill.

Proc. U. S. Nat. Mus., vol. xvii, p. 286, 1894.

B. range, 1054 to 1060 fath. Taken twice by the U. S. Fish Comm., at N. lat. 39° 46' 30" and 39° 43′ 30′′.

FREYELLA ASPERA Verrill.

Freyella aspera Verrill, Proc. U. S. Nat. Mus., vol. xvii, p. 285, 1894.

B. range, 1917 fath. One specimen was dredged at N. lat. 37° 59' 20", off Chesapeake Bay.

Fragments of a fourth species of Freyella were dredged at Sta. 2077, N. lat. 41° 09, in 1255 fath.

Bathymetrical Distribution of the Families of Asterioidea, in this Region. [The numerals refer to the number of species found in each zone of depth.*]

*The slight differences in the numbers here given, as compared with the list on page 128, is due to the discovery of a few additional species after the first part of this paper was printed.

ART. XX.-Drift Bowlders between the Mohawk and Susquehanna Rivers; by ALBERT P. BRIGHAM.

THE district traversed in my investigations extends from Utica on the Mohawk River, south-south-westward to the confluence of the Chenango and Susquehanna Rivers at Binghamton, a distance of 95 miles. It is approximately the line of the Oriskany and Chenango valleys; or of the New York, Ontario. and Western Railway from Utica to Oxford and the Delaware, Lackawanna and Western Railway from Utica to Binghamton. The main valleys, valley slopes and summits of the hill ranges were seen continuously for the first 40 miles from the Mohawk, and over a breadth of from 10 to 20 miles. Farther south a series of points was selected, with observations at all altitudes. Topography.-The district belongs to the plateau region of central and southern New York, dropping down to the level of the Mohawk valley on the north. The Mohawk-Susquehanna divide averages 20 miles distance from the Mohawk River. From this divide extend northward and southward the valleys and hill ranges which are characteristic of central and western New York. The northern slope is drained by the Sauquoit, Oriskany, and Oneida Creeks; the southern slope carries the Chenango, Unadilla and Susquehanna Rivers. The divides in the region considered are: Cassville, altitude 1215 feet; Waterville, 1238 feet; Bouckville, 1147 feet; Pratts, altitude not known, but somewhat greater than that of Bouckville. At Rome we have 445 feet and at Utica, 410 feet. South of the divide the record is: Hamilton, 1111 feet; Norwich, 1001 feet; Binghamton, D. and L. and W. R. R., 846 feet; Binghamton, Susquehanna River 814 feet. The hills rise from 500 to 700 feet above the adjacent valleys, culminating in Tassel Hill, Paris, Oneida County, 1948 feet. Comparing the railway levels at Utica, and Binghamton with the summit at Bouckville, it will be seen that we descend northward 737 feet in 24 miles, and southward 301 feet in 71 miles, making the average northern slope of the valley bottoms 30.71 feet per mile; average southern slope 4.24 feet per mile. The distances are taken from the railroads. Air line measurement would slightly change the figures. From a limited number of aneroid determinations it is thought that the altitude of the hill ranges is even more sustained going southward, than that of the valley bottoms. The writer hopes to discuss the meaning of these facts in a later paper on the topographic history of the Chenango Valley region. Four sections of the moraine. described by Professor Chamberlin,* lie within the field of this

* Terminal Moraine, etc., 3d Ann. Rep. U. S. G. S., p. 360.

paper; viz: from Sauquoit to Cassville; about Waterville; from Deansville to Solsville, and from Munnsville to Pratts. These all stretch up the north flowing streams to about the position of the divides in the respective valleys. Extensive valley trains appear southward, with recurrent terraces and kames throughout the Chenango valley.

The Geological Formations.-The conditions are excellent for the determination of linear (southward) and vertical distribution of bowlders, from the manner in which narrow lines of outcrop cross the track of the ice. It is evident that we have here no such conditions for the study of lateral distribution as are afforded by Iron Hill in Rhode Island,* and the

*N. S. Shaler, Bowlder Train from Iron Hill, Bull. Mus. Comp. Zool., vol. xvi, No. 11.

quartzite knobs of Wisconsin.* The pre-Paleozoic rocks referred to in this paper are for convenience classed as Archæan. The nearest outcrops, except by faulting at Little Falls, are at the southwestern base of the Adirondacks, 30 miles from Utica. The Cambrian is represented by the Potsdam sandstone of St. Lawrence, Jefferson and Lewis Counties. The Ordovician consists of Calciferous, Trenton, Utica and Hudson River, outcropping in a nearly N. W. by S. E. direction, only the Utica and Hudson River appearing as far south as the Mohawk valley, in this region. The Silurian beds, Oneida-Medina, Clinton, Niagara, Salina and Lower Helderberg, cross our field in nearly east and west bands, and as a whole extend south to Oriskany Falls. It is evident from the sharp descent from the divide to the Mohawk, that the outcrops must be narrow and that the bottom ice was pushed up across their bevelled edges. The Devonian column begins with the Oriskany sandstone, Corniferous and Marcellus about Oriskany Falls and Waterville and passes to a broad band of Hamilton extending southward to Smyrna, where it is succeeded by the Upper Devonian members, continuing to Binghamton. Of the above masses, the Calciferous and Trenton have not been recognized within the field studied, though they doubtless exist in small fragments. The older and more distant Potsdam forms a quite constant element in our drift, being composed, both in its cement and constituent grains, of nearly pure quartz. But without microscopic examination it is in danger of being confused with certain Medina and Clinton fragments which resemble it in color. The Utica, Salina and Marcellus are too soft for massive transportation beyond short distances. The sandstones of the Hudson River, and to a large extent of the Clinton, have not afforded ready identification, being largely without fossils and weathering to a non-committal brown. The Niagara is very thin in Oneida County, though a certain peculiar structure is very characteristic, and four or five pebbles have been found from 20 to 50 miles from its outcrop. The main reliance has been upon the Archæan, Oneida, Lower Helderberg, Oriskany Sandstone and Corniferous. separate discussion of these terranes and their bowlders will follow. Sandstones of the Hamilton and several of the higher

* Ira M. Buell, Trans. Wis. Acad. Sci., ix, pp. 255-274; Cf. T. C. Chamberlin, Jour. Geol., i. pp. 255-267.

Since writing the above, Professor C. H. Smyth, Jr. has kindly subjected to microscopic examination a representative fragment from my specimens, finding it to be a thoroughly indurated quartzite, not likely to be matched in any of our lower Paleozoic horizons save the Potsdam.

On limitation of identification, see, The Drift-its Characteristics and Relationships, R. D. Salisbury, Jour. Geol., vol. ii, Oct.-Nov., 1894, p. 717. Vanuxem, Geol. 3d. Dist. N. Y., pp. 92, 93.

members weather to monotonous browns and grays and would need careful attention to their fossil contents for trustworthy identification.

The dip of these beds, in connection with the dissection of the region into north and south trenches and ridges, is an essential fact in the study of vertical distribution, or of the plucking action of the ice. The several terranes first appear, as one goes southward, in northward loops on the hills, and disappear as southward loops in the valleys. Vanuxem cites a measurement for the Corniferous near Waterville, as 27 feet per mile S. W. The Oriskany sandstone at Oriskany Falls dips 47 feet per mile. 40 to 50 feet per mile, S. S. W. is probably a safe general statement for the region.

General Movement of the Ice.-Striæ observed at several localities indicate that the main movement of the glacial current was about S. 20° W. This conclusion is based upon comparison and averaging of movements at the higher altitudes, and where local topography would not be likely to modify direction. The trend may have been largely influenced by the Adirondacks as a local center of glaciation. If this be true, a S. S. W. flow along the Oriskany-Chenango axis is radial and would be expected. The Hudson River and Oneida bowlders of our field may thus have been plucked from the vicinity of Utica and Rome, although some were doubtless brought in by cross currents from more easterly and westerly points.

A

Archæan Boulders. These fragments of the drift are in the usual lithological variety. No consideration of them relative to their sources, can be had, until their Adirondack and more northerly localities shall have been studied in detail.* A profusion of large Archæan masses is found in northern Oneida County, over the Paleozoic terranes which lie within a few miles of the crystalline areas. For some miles south of the Mohawk, pieces having diameters of four feet are tolerably frequent. South of the divide such fragments are rare. few comparisons from counts and estimates made in the field, will give the best notion of the facts. Approaching Oriskany Falls from Clinton, on the summit of the range to the westward, six Archæan pieces were observed having axes of four to six feet. These and many smaller ones were seen in increasing numbers on nearing the line of the moraine, which appears in its full strength in the valley at the above village. The valley moraine itself however, consists of kames, which are nearly free from large bowlders. Thirty feet of stone wall in the town of Madison, showing average complexion of bowlders of the adjacent field, give the following result.

*For notes on such comparative study, see G. F. Wright on the Glacial Boundary, Bull. 58, U. S. G. S., pp. 50-52.