Natural History. 361 



earth was pushed up in a heap, so as to rise above the water, de- 

 clining at the distance of a few inches obliquely and rapidly. A 

 little way off was a smaller rock, exhibiting similar phenomena. 



Another instance is referred to by Dr. Dwight described in 

 the Collections of the Massacliusetts' Society. It is stated that, 

 at the bottom of a cove in the long pond in Bridgeton, are stones 

 of various sizes, which, it is evident from visible circumstances, 

 have an annual motion towards the shore, the proofs being that 

 marks or tracks are left behind them, and bodies of clay driven 

 up before them. Some, perhaps two or three tons in weight, have 

 left a track several rods behind them, having at least a common 

 cart-load of clay before them. These stones are many of theril 

 covered with water at all seasons of the year. The shore of the 

 cove is lined with these stones three feet deep, which it would 

 seem have crawled out of the water. 



The Rev. J. Adams, who endeavours to explain these pheno- 

 mena, states that there is a pond in Rhode Island, where similar 

 phenomena are seen. He considers the expansive power of ice 

 as fully sufficient to art!Ount for the effects observed ; explaining 

 them by supposing that the ice which, at an early period of its 

 formation, had become fast attached to the stones, had then, as in 

 its continued formation it expanded from the middle outwards, 

 thrust them towards the shore. The expansion from the middle 

 outwards he states to be well known to those acquainted with cold 

 climates, and have observed the formation of ice ; and mentions, that 

 in large ponds and lakes, where thick ice has been fonned, he has 

 observed a disruption just at the edge, between the main body of 

 ice and the shore take place, and the ice has projected on the 

 shore a considerable distance over the line of disruption. Re- 

 petition of this effort, it is considered, would easily account for 

 the motions of the stones. 



In confirmation of this effect he remarks, that in New England, 

 fences which originally stood erect near the edge of grounds, 

 covered by water during the winter, have considerably inclined 

 towards the shore as soon as the ice was formed, such fences al- 

 ways requiring to be placed upright in the spring. It is well 

 known also among the farmers of New England, that if a stone 

 fence be erected in a similar situation, it will after some time be 

 overturned. 



With reference to the cove at Bridgeton being lined with stones, 

 which had apparently crawled out of the water, he remarks that 

 many ponds and lakes in New England are lined with rocks in 

 the same manner. While bathing on such shores he has fre- 

 quently found a gravel bottom quite free from stones, until he 

 had advanced to the depth of about three feet, when suddenly the 

 bottom was covered with stones as far as he could reach it, in size 

 and other respects, like those with which the shore was lined. 



