GLACIAL EROSION AND TRANSPORTATION. 237 



erland. Professor Forbes describes another bowlder in the 

 Alps, one hundred feet long and forty to fifty feet high ; also 

 another, sixty-two feet in diameter, containing 244,000 cubic 

 feet. In this country bowlders occur of equal dimensions. 

 Thus, on Cape Ann and its vicinity, I have not unfrequently 

 met with blocks of syenite not less than thirty feet in diame- 

 ter ; and in the southeast part of Bradford (Mass.) I noticed 

 one thirty feet square, which contains 27,000 cubic feet, and 

 weighs not less than 2,310 tons. In the west part of Sand- 

 wich, on Cape Cod, I have seen many bowlders of granitic 

 gneiss twenty feet in diameter, which contain 8,000 cubic feet, 

 and weigh as much as 680 tons. Two sandstone bowlders of 

 the same size lie a few rods distant from the meeting-house in 

 Norton. A granite bowlder of equal dimensions lies about half 

 a mile southeast of the meeting-house in Warwick ; and one of 

 similar dimensions lies on the western slope of Hoosac Mountain, 

 in the northeast part of Adams, at least one thousand feet above 

 the valley over which it must have been transported. One of 

 granite lies at the foot of the cliffs at Gay Head, on Martha's 

 Vineyard, which is ninety feet in circumference, and weighs 

 1,447 tons. In Winchester, N. H., I recently met with a block 

 of granite eighty-six feet in circumference. It is near the road 

 leading to Richmond. I noticed another in Antrim, in that 

 State, one hundred and fifty feet in horizontal circumference. 

 Finally, at Fall River was a bowlder of conglomerate which 

 originally weighed 5,400 tons, or 10,800,000 pounds.* 



A well-known bowlder in eastern Massachusetts, situated 

 on a precipitous cliff in the southern part of the town of 

 Peabody, goes by the name of Ship Rock. This is a gran- 

 ite, and measures forty-five feet in length by twenty-two in 

 height, and twenty-five in width. Its estimated weight is 

 1,100 tons, and it is surrounded by many loose fragments 

 weighing from fifty to seventy-five tons each. This rock 

 has been purchased by the Essex Institute of Salem, and is 

 carefully preserved from destruction, f 



* " Elementary Geology," pp. 242, 243. 



f See " Journal of Essex County Natural History Society," p. 120. 



