ANDOVER AND HAVERHILL SERIES OF KAMES. 169 



and descends into river valleys in a certain apparent independence of the natural con- 

 figuration of the country. Tlie laud, however, though undulating and somewhat 

 broken, nowhere in this part of Massachusetts rises more than 300 or 400 feet above 

 tide-water; and even these heights are reached only by peculiar accumulations of un- 

 modified drift or till, which here forms massive rounded hills. The gravel ridges 

 plainly belong to the superficial deposit, since they everywhere overlie the ground- 

 moraine or till. They rest upon the flanks of these hills at Lawrence near the reser- 

 voir ; at Ballard Vale, on Pole hill ; at Wakefield, near the rattan works ; in the north- 

 east part of Middleton ; and on the north bank of the Merrimack in Haverhill, opposite 

 to and a little below Groveland. 



Sometimes the ridges disappear in a sandy plain, in which case, however, there are 

 usually bowl-shaped depressions in the plain along the line of general direction. This 

 is noticeable east of Ballard Vale. These depressions are frequent in Kingston, N. H., 

 near Great pond. But the most remarkable instance is near the cemetery in Marble- 

 head, a half mile south-east from the lead mills in Salem. Here is a cluster of depres- 

 sions within a depression. The outer rim has a north-to-south diameter of 605 feet, 

 and an east-to-west diameter of 735 feet. A hollow at the south side descends to the 

 tide-level, with a depth of 60 feet and an east-to-west diameter at the top of 360 feet. 

 A similar though shallower hollow occurs at the north-west side. Numerous minor 

 depressions intervene. The material of these circular ridges is partly of local origin, 

 and partly not. Plant them upon higher ground, and they would be called the reticu- 

 lated portion of a kame. Many lakelets are but these depressions full of water. 



These ridges have been found in two well defined series, as shown in Map 3, Plate 

 VII. The westernmost or Atidover series may be represented in Rockingham county 

 by kames observed near the Manchester & Lawrence Railroad, north-west from Wil- 

 son's crossing in Londonderry, near West Derry station, and at a point a mile and a 

 half farther south on the west side of the railroad ; also near Goss pond in the south- 

 east part of Londonderry, where there are bowl-shaped depressions, and thence south- 

 ward to West Windham station on the Nashua & Rochester Railroad ; also near a 

 granite quarry a half mile west from Salem Depot. 



In Massachusetts this series extends through Methuen, Lawrence, Andover, North 

 Reading, Reading, Lynnfield, Wakefield, and Melrose, terminating near the south end 

 of Prospect hill in Maiden. It is continuous from Messer's crossing and Mystic pond 

 in Methuen to the pumping-station of the Lawrence water-works, being well shown on 

 the hillside south-east of the reservoir. On the low land near Spicket river these 

 ridges show stratification ; but higher up, as north-west of the Catholic cemetery, they 

 are for the most part unstratified. Bowl-shaped depressions abound. 



This series is finely developed near Andover, as shown in Maps i and 2, forming the 

 banks of Pomp's, Foster's, and Martin's ponds. Numerous sections of these ridges 

 show the central portion unstratified, the pebbles of large size being in and resting on 

 the clay, loam, and unwashed sand ; but sometimes we find stratified material under 

 an unstratified mass, or pockets of partly stratified material in the unstratified. 

 VOL. in. 22 



