310 SURFACE GEOLOGY. 



Lake Ramparts. 



Under this name I have described in earlier state reports ridges of 

 boulders and coarse gravel bordering certain portions of shallow ponds. 

 They occur where the water is not deep, and there is a considerable 

 exposure of shoal bottom strown with boulders. As the water freezes in 

 the winter the ice encloses these stones, and by virtue of expansion 

 moves them nearer the shore. The amount of pushing in a single sea- 

 son would be small ; but the work would be resumed every winter, and 

 in the course of ages the fragments would reach the shore, and perhaps 

 be crowded inland. Farmers who build fences on the edges of a wide 

 ditch often find them bent or prostrated in the spring for a similar rea- 

 son ; the expansion of the water in freezing has jDushed them over. 



Several instances of these ridges have been observed in New Hamp- 

 shire. The best known is on the Vaughan shore in Moultonborough, in 

 the north-east part of Lake Winnipiseogee. We find there a ridge one 

 eighth of a mile long, opposite a broad expanse of shallow water about 

 four feet in height. Passing easterly 125 feet, the ground is low and 

 swampy, and another similar ridge about fifteen feet high is encountered, 

 fronting a low terrace. It is very hkely this ridge represents an older 

 rampart, made when the lake stood at a higher level. The shore and 

 the ridges are covered by shrubs and trees. A pine had been cut re- 

 cently from the smaller rampart, whose trunk has a diameter of twenty- 

 eight inches. From this I obtained a section for the museum, and 

 counted 122 rings of growth upon it. As this had been cut twenty-five 

 years previous to my visit (1871), it is obvious that certainly a century 

 has elapsed since the formation of the rampart. I saw 

 a tree still standing upon this ridge twenty-seven inches 

 in diameter. A few years since, in the case of the town 

 of Gilford v. The Winnipi- 

 seogee Lake Company, it 



was found expedient to use 



Fig. 62.— Lake Rampart, Moultonborough. .i r i. 1 i ,.1 • 



^ the facts shown by this ram- 



part with the trees upon it, to prove that there had been no unusual 

 flowage of the lake for the past hundred years. The whole court ad- 

 journed to visit the locality. Fig. 62 shows the two ramparts with a tree 



