Glacier Work. — Scott. 259 
rounded contour. These embrace almost every form of mounds, 
knolls, hummocks, and serpentine ridges, frequently inter- 
spersed with depressions of a striking character and known by 
a variety of names as "kettle-holes, "sinks," et cetera. These 
depressions, of variable depth and area, and from a few feet 
to a hundred feet across, are not infrequently partially filled 
with water in such a way as to lend to the general topography 
a very distinctive and charming appearance. 
In many cases a form of deposit is recognized as "valley 
drift' which represents the overwash from a terminal moraine, 
and consists chiefly of a plain of stratified gravel. At a greater 
distance from the moraine is found the finer material which 
naturally would be held in suspension for a longer time by the 
glacial streams. The deposits like the fluvial deposits of loess 
in the Mississippi valley are of such origin. It is thought prob- 
able, however, that some of the loess deposits of this and other 
regions are only indirectly due to glacier action, having been 
deposited by winds acting on glacio-fluvial material. 
In both Europe and America the glacial deposits increase 
in thickness and variety from South to North. The most re- 
cent of the two terminal moraines in America begins on the 
Atlantic border of Massachusetts where it is in part submerged, 
rises to prominence in Nantucket island, Martha's A'liieyard, 
and Block Island whence it is prolonged to Lor\g Island, there 
reaching a hight of 200 or 300 feet. Another line of drift 
hills passes along the northern part of Long Island, embraces 
Fisher's island, and the southern end of the state of Rhode 
Island, thence to the Elizabeth islands and on into the state 
of Massachusetts. From the western end of Long Island the 
moraine passes across Staten island and northern New Jersey 
into Pennsylvania; thence northwesterly across that (State and 
a part of New York, whence it turns to the southwest and again 
enters Pennsylvania, and passes on into Ohio, extending across 
the central part of that state and Indiana. Thence it takes a 
northwesterly direction crossing parts of Illinois, Wisconsin, 
and Minnesota, chpping into the center of Iowa as far south as 
DesMoines, and thence passing over Dakota into the British 
possessions. A summary bv professor Chamberlin * shows 
that this morainic belt characteristically persists over a course 
♦Preliminary Paper on the TLiminal Moi-aine, ;{d Ann. RejU.. U. S. 
Geol. Survey, 18S3. 
