70 The American Geologist. August, 1894 
during attendance at the last summer meeting of this society. 
We may best understand the structure and origin of this 
peculiar class or type of drumlins, here named the Madison 
type from the city where it is so finely displayed, by noticing 
in the foregoing order its several gradations of development. 
Great Head, five miles northeast of Boston, is an excellent 
example of the many drumlins which form the islands of 
Boston harbor and abound in all the surrounding cities and 
towns to a distance of five to ten miles or more from the state 
house. Other examples are Beacon hill in Boston ; Bunker 
hill in Charlestown; Prospect and Winter hills in Somerville : 
the Observatory hill in Cambridge: Corey hill in Brookline : 
Chestnut and Institute hills in Newton; Bellevue hill in West 
Roxbury; Mt. Bowdoin in Dorchester: the Wollaston flights. 
Forbes, and President's hills, in Quincy; Great hill in Wey- 
mouth: Baker's and Prospect hills in Hingham ; all the hills 
of the Nantasket peninsula : Scituate hill inCohasset: and 
First, Second, Third, and Fourth Cliffs, in Scituate. 
These drumlins, which were formerly known by Prof. ('. II. 
Hitchcock's designation as lenticular hills of till or unmodi- 
fied glacial drift, attain bights varying from 30 to 200 feet 
above their bases. Their crests in this district of Boston and 
its neighborhood adjoining Massachusetts bay are at all alti- 
tudes from very near the sea level up to 350 feet above it. 
They have in most cases very smoothly oval, gracefully mould- 
ed outlines, with steep slopes on each side, more gentle ascent 
at each end, and a beautifully rounded top. In area they 
range, in proportion to their flights, from a length of a few 
hundred feet to about a mile, with usually half or two-thirds 
as great width. Their longer axes here trend southeasterly 
and vary in direction from south-southeast to east-southeast. 
baking the courses of the latest currents of the ice-sheet up- 
on this area. Though drumlins are distributed in profusion 
on this part of our coast, they are also found in equal abund- 
ance upon large inland tracts of Massachusetts and south- 
ern New Hampshire, to hights of f ,500 feet above the sea in 
the vicinity of Monadnock mountain, on the watershed be- 
tween the Merrimack and Connecticut rivers. Their numbers 
mapped by me in New Hampshire, under the direction of 
Professor Hitchcock for the Geological Survey of that state. 
