36 On certain Rocks supposed to move. 



r 



pass of nearly a mile, no such eminences appear. But I 

 shall perhaps throw some hght upon this, when I come to 

 those rocks which move. The third argument which might 

 be adduced, is the situation of the rocks. This neck of 

 land (I mean that part of it which is not alluvial,) is nearly 

 of the same width throughout. Were not some of the rock^ 

 of which it is composed, of such a size, we should uridoubt- 

 edly be led to suppose it an artificial causeway. Does not 

 this equality, or uniformity of width, favor my supposition? 



As to the moving rocks, I made such observations as my 

 short stay in the place would permit. This phenomenon 

 was known to the first inhabitants of the town. Its proba- 

 bility was suggested by their own observation, and its truth 

 established by actual measurements. From the gentleman 

 with whom I visited the spot, I obtained the following meas- 

 urement. Its correctness may be implicitly relied on. 



Sept. 1819. The distance from the largest rock to a cer- 

 tain birch tree on the shore, was 15 rods 39 links- 



Feb. 13,1821. The distance of the same rock to the sanfe 

 tree, was 12 rods 371 links. Subtracting 12 — 37 from 

 15- — 39, leaves 3 rods 2 links, which this rock moved in 

 less than eighteen months. The same gentleman measured 

 it each time, and used the same chain iu both. 



Twelve* years ago It moved but five feet in a year. Its 

 motion is therefore accelerated as it approaches the shore. 

 I have spoken particularly of this rock, because it is the on- 

 ly one whose exact progress has been ascertained. All the 



stones however. In this part of the lake, move, from the lar- 

 gest to the smallest, and leav^e a track or trench behind 

 them, of greater or less magnitude, in proportion to the size of 

 the stone. The largest rock (and it probably weighs forty 

 or fifty tons,) has ploughed up the sand and gravel before it 



*The island marked E is about threeqiiarteraof a mile from tlie shore. It 

 is composed of mica slate, lying on a bed of limestone ; large masses of the 

 latter lie on t!ie shore of the island. You will Bee by a simple calculation, 

 th^t, at the present rate of moving, they will reach the opposite shore in les« 

 than a buudred years. That those masses composing the foundation oi 

 the road came from theuce, 1 will not pretend to say. 



The mineral I oh^-erved in Salisbury are the following: — Tremolite ra- 

 difttetl, stellated with fibres nearly two feet long; Garnets in abundance; 

 Staurotidp; black and white Mica; Jasper; Sulphat of , Iron ; Alumine; 

 Iron ore — all varieties ; generally the brown Iron stone of Werner; Dolo- 

 mite; Ca. bona te of Lime; Mica slate ; Clay; Ochres, &:c. of various kinds* 

 Some Copper, in the Iron-ore lately found- 



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