BETHLEHEM MORAINE 271 



topography, especially the ravines on Mount Lafayette, observation and 

 mapping of the moraines in question,- and an investigation of the direction 

 of dispersion of boulders in the drift. 



TOPOGRAPHY OF THE MORAINE 



The Bethlehem moraine field is neither a series of distinct and separate 

 recessional moraines, like those of the Rhone, nor an "indivisible and 

 promiscuous morainic belt," although as a general statement the latter 

 description comes nearer the truth. The fact is, the Ammonoosuc Valley 

 north of Bethlehem and Maplewood and westward from Bethlehem Junc- 

 tion as far as Littleton is occupied by a group or chain of recessional 

 moraines whose thickness in places probably exceeds 300 feet. This is 

 shown on the map, plate 13. The belt can be resolved into its component 

 parts only by making a thorough traverse of the district on foot and 

 giving full attention to topographic detail, such as linear mounds and 

 boulder belts, the alignment of sags and swells, and of knobs and kettles 

 and of intervening belts of smoother surface. In a few places the irregu- 

 larity of surface is strong enough to gain recognition in the 30-foot con- 

 tours of the Whitefiekl quadrangle of the United States Geological Sur- 

 vey, in spite of overgeneralization and failure to portray index forms to 

 the degree now observed by the topographers of the Survey. Thus about 

 a mile southwest of Wing Boad, where the road to Bethlehem reaches the 

 top of the hill, depression contours show two undrained hollows whose 

 depth considerably exceeds 30 feet. They are in fact very conspicuous 

 steep-sided kettle-holes, surrounded by high knobs of one of the most 

 pronounced and continuous morainic lines in the district. Linear de- 

 velopment of morainic ridges is also suggested where contours between 

 1,300 and 1,300 feet across the north-south road, a mile and a half west 

 of Bethlehem. Although the kamelike mounds and gentler swells are in 

 many places subcircular, or, when linear, are oriented without order, 

 there is a prevalent east-west trend, or, more accurately, a trend of north 

 65° east-south 65° west, which is apparent at once to one who traverses 

 the field on foot, and is shown on the map, plate 13. In, the district 

 between the Bethlehem-Littleton State road and the Ammonoosuc River 

 only one exposure of bedrock was discovered during a week of search. 

 This is a few rods southwest of a little ice pond a mile north of Bethle- 

 hem village. Rock exposures occur in the Ammonoosuc River at Apthorp 

 (near Littleton) and above the mouth of Alder Brook; but the hills south 

 of it, which rise from 300 to 400 feet higher, seem to be completely cov- 

 ered by, and largely composed of, glacial drift. In a large' degree, there- 

 fore, the course of the Ammonoosuc between Wing Road and Littleton 



