312 Roger’s Account of two Remarkable 
chain, in Canaan, New York, a little west of the Massachusetts 
line, and about four miles south of the Lebanon Springs, we 
may perceive two remarkable trains of thinly scattered erratic 
blocks, stretching, for many miles, in a south-easterly direction, 
across the valleys, and up and over the parallel intervening 
mountain barriers of Berkshire. These trains are of extra- 
ordinary length ; the most northerly of the two extending, ac- 
cording to the observations of Dr. Reid, who has traced them 
over the fields, and through tracts of forest, a distance of 
nearly twenty miles. They are only approximately. straight 
and parallel, for they bend sensibly at several points, and 
diverge a little as they recede from their place of origin. 
Their average width is about three or four hundred feet, and 
the distance between them is from one third to one half of a 
mile. 
The blocks composing these trains are, for the most part, 
of enormous size ; the smaller ones being generally several feet 
in diameter, while others are ten or twenty feet, and a few are 
even thirty feet or more. One of the largest lies not far from 
the residence of Dr. Reid, in the neighborhood of Richmond 
meeting-house, and therefore nearly four miles from its source. 
It has been ascertained by him to be nearly fifty feet long, 
forty feet wide, and about fifteen feet thick, five feet of its 
thickness being imbedded in the gravelly drift. Its weight 
probably exceeds two thousand tons. The fragments, in both 
trains, are rather thinly scattered, the distances between them 
being generally several times their own dimensions ; but there 
are localities where they lie almost in contact. : 
While these erratics are of various sizes in the same neigh- 
borhood, there is a perceptible, though, of course, very gradual, 
diminution in their average bulk, as we follow them to the 
south-east. It is true, blocks of very great magnitude, like 
the one just referred to, are met with, even several miles 
remote from their parent stratum ; but, when we compare the 
mean size of the fragments, at any given locality, with that - 
another spot, a mile or two further on, we discover an obvious 
