282 GEOLOGY. 



not exceed a cubic foot, they sometimes reach thousands 

 of cubic feet in size, and thousands of tons in weight. 

 The boulder on which the colossal statue of Peter the 

 Great stands in St. Petersburg is a mass of granite 

 weighing 1500 tons. A boulder at Whittingham, Vt., a 

 town in the Green Mountains, is 43 feet long and 32 in 

 average width, contains 40,000 cubic feet, and weighs 

 3400 tons. The distances to which boulders have been 

 transported have been much investigated. The ordinary 

 distances are from 20 to 40 miles, but they have often 

 been carried 60, or even 100 miles. Hitchcock speaks 

 of some boulders found in Ohio and Michigan which 

 came from the ancient azoic rocks of Canada, and calcu- 

 lates that they must have been brought from a distance 

 of from 400 to 600 miles. These distances are discov- 

 ered by comparing the boulders with the rocks of the 

 country, thus tracing them back to the sources from 

 which they came. Sometimes great boulders have been 

 carried across deep valleys. Thus the monstrous one in 

 Whittingham was transported across a valley 1000 feet 

 deep, and another on the Hoosac Mountain, in Massa- 

 chusetts, came across a valley 1300 feet deep. 



Sometimes many square miles are almost covered with 

 boulders of various sizes. This is often seen in the hilly 

 parts of New England. A singular circumstance in re- 

 gard to the disposition of boulders, first pointed out by 

 Hitchcock, is the arrangement of them in long trains. 

 There are two nearly parallel trains in Massachusetts, 

 extending from between Canaan and Lebanon, one of 

 them to a distance of 20 miles and the other 10. They 

 are from 300 to 400 feet in width, and are about half a 

 mile apart. It is a singular fact that they cross two 

 ranges of mountains which are 100 feet higher than the 

 source from which the stones came. The boulders are 

 most of them large, one of them weighing over 2000 

 tons, and their angles are but little rounded, showing 

 that they have been subjected to but little friction. Did 



