80 THE BUTTERFLIES OF NEW ENGLAND. 



chusetts and the eastern third of the rest of the State, New Hampshire 

 from Lake Winnipiseogee to the coast, and fully a third of Maine. This 

 reo-ion is by no means as level as the coastal plain of New Jersey and 

 the Atlantic border farther south, but is irregularly broken by rocky hills 

 among flat, drift lowlands. Some of the elevations might rank with small 

 mountains, as the Blue Hills (635), a little south of Boston, and in Maine, 

 Agamenticus (673) back of York, and Green Mountain (1527) on Mt. 

 Desert. On the other hand, large areas are wanting in rocky hills, as in 

 southeastern New Hampshire, and all of Massachusetts below Plymouth. 

 Cape Cod and the islands to the south and west are essentially the product 

 of orlacial action, which is next to be considered. 



It was over a country whose larger divisions have now been described 

 that the quaternary ice-sheets crept down from the north. The ice 

 scoured out the valleys, smoothing off the spurs and ridges on their sides. 

 Crawford's Notch in the AVhite Mountains, through which a heavy stream 

 of ice must have flowed, is probably as good an example as we possess of 

 a valley form thus simplified. The glacial sheet rose and covered all the 

 hills and wore down their peaks and pinnacles : Mt. Monadnock, whose 

 structure is well adapted to develop a ragged crest-line, has lost many of 

 the sharp edges that it must once have had, and over its rounded summits, 

 the marks of ice-dragged stones are plainly visible. The total effect of the 

 glacial invasion was most likely towards diminishing the topographic relief 

 of New England, not only by rubbing down the hills and ridges, but even 

 more by leaving the drift-rubbish chiefly on the lower ground, greatly to 

 the embarrassment of the streams that took possession of the country again 

 as the ice melted away. 



The ground moraine, the immediate product of the moving ice-sheet on 

 the ground beneath it, known by the Scotch name, till, is generally absent 

 from the higher, steeper hills, but is spread with smoothly rolling surface, 

 somewhat fluted in the direction of ice-motion, over the lowlands and flat 

 uplands. The contrast between the upper zone of glacial erosion and the 

 lower zone of drift accumulation is admirably shown in the smaller side 

 valleys among the Berkshire hills of Western Massachusetts. In central 

 and southern New England, the till often takes the form of oval, rounded 

 hills of evenly arched profile, now known by the Irish name, drumlins ; the 

 largest of these are over half a mile in length and rise more than two hun- 

 dred feet above their base : they are seen about Boston, where they make 

 the harbor islands, and again on the uplands about Brookfield, j\lass., 

 and west of Putnam, Conn., where they control the shape of the country. 

 Heaps of drift, forming hills and enclosing hollows of marked topographic 

 value, known by the Swiss name, moraines, mark the position held by the 

 edge of the ice-sheet during a time of balanced supply and waste : great 

 terminal moraines may be traced over Cape Cod and the islands to the south 



