1889.] 
237 
[Upham. 
by intervals that vary from three to six feet ; at the southwest end 
of Long Island, where a single dark band about half-way up the 
cliff, or 30 to 40 feet above the sea, extends fully 400 feet ; and at 
the south end of Spectacle Island, where two dark bands six or 
eight feet apart are distinctly seen along a distance of at least 150 
feet, at a similar elevation above the sea and below the top of the cliff 
as on Long Island. In all these sections, as in Third Cliff, Scitu- 
ate, the dark bands have anticlinal dips, which are somewhat more 
inclined than the overlying arched surface. On the islands of the 
harbor this structure is best seen in sailing by within a short dis- 
tance ; and my attention was first directed to it by Prof. W. O. 
Crosby in a yachting excursion. Its significance as evidence that 
the deposition of till was in progress contemporaneously upon a 
former surface of the growing drumlin is nearly the same that is 
occasionally otherwise indicated by lines of more plentiful boulders 
than the average in other parts of the till deposit. Such a line of 
exceptionally abundant boulders and small rock-fragments, of sizes 
from a few inches to two or three feet in diameter, I noted in the 
cliff at the east end of the drumlin close south of Point Allerton, 
extending 50 or 75 feet in its northern slope about six feet below 
the surface ; and another, of similar situation and extent, is seen in 
the till of Walnut or College Hill, Medford, where it is cut by Cur- 
tis street. 1 
Thick beds of modified drift enclosed in the lower part of drum- 
lins and overlain by their accumulations of till are certainly very 
rare. My only observations of them in eastern Massachusetts are 
the two sections in Scituate already described ; and the only other 
notes of their occurrence in this district that have come to my knowl- 
edge are those of Mr. W. W. Dodge, who saw in the base of Great 
Head, Winthrop, exposed by excavation for a railroad, an anti- 
clinal deposit of fine gravel overlain by till, as in Third and Fourth 
Cliffs, 2 and who further informs me that when Fort Hill in Boston, 
Compare Prof. H. Y. Hind’s notes of the arrangement of boulders in the till at 
Toronto, Ontario (Report ot the Assiniboine and Saskatchewan Exploring Expedition, 
Toronto, 1859, p. 120); my observations of a buried moraine in Big Stone, Swift and 
Chippewa counties, Minnesota (Geology of Minn., Eighth annual report, for 1879, p. 
116; do., Final Report, vol. ii, 1888, p. 214, noting in one locality a striated pavement of 
boulders) ; and Mr. Hugh Miller’s suggestive paper, l 'On Fluxion-Structure in Till” 
(Report of the Brit. Assoc, for Adv. of Science, Montreal, 1884, p. 720; Geol. Mag., m, 
vol. i, 1884, p.472). 
2 Am.Jour. Sci.,m, vol. xxxvi, p. 56, July, 1888; Proceedings of this Society, vol. 
xxiv, p. 132, Dec., 1888. 
