MUSEUM OF COMPARATIVE ZOOLOGY. 191 
the fluid by hot stones, —a method much practised by the Indians and 
other primitive people, and still in use by our farmers. Therefore it is 
not surprising that occasional specimens are found beyond the limits of 
the boulder train, but in many weeks of search I have never discovered 
a fragment away from the trail which did not by its present use or its 
association with other objects indicate that it had been artificially trans- 
ported. Only three boulders have been found to the north of the hill. 
These were rounded bits, such as may have been used by Indians or 
whites in various simple arts. As will be seen from the’ description of 
the glacial trail, the pebbles within its belt are extremely numerous, 
constituting for some miles of distance a considerable percentage of these 
drift materials. Therefore these sporadic fragments, always of small 
size, but not the smallest, and of a form likely to commend themselves 
for the before mentioned uses, need not excite suspicion that there are 
other and unlooked for sources of this material which may serve to 
confuse the indications which the train affords. The form of the train, 
so far as it is traceable, and the condition of the fragments at equal dis- 
tances from the apparent source, alike indicate that all the materials 
which it contains have been derived from one locality. Throughout the 
observable portions of its extension, the train steadfastly and uniformly 
widens, and the fragments of peridotite grow smaller with the increase 
of distance from the source of the material. 
At no other point in New England has an ore which could be con- 
founded with this from Iron Hill been discovered; nor, so far as I can 
learn, has a rock of like aspect been observed in any other part of this 
country. It seems therefore safe to assume that this boulder train 
affords excellent evidence as to the conditions which brought about the 
transportation of its fragments. 
The rock of which the Iron Hill is composed has been a good deal 
used in making pig-iron. From time to time the material has been 
quarried and exported to furnaces in New York and Pennsylvania. The 
large amount of ilmenite which it contains makes it an unsatisfactory 
ore, but the absence of phosphorus and the small amount of sulphur 
tempt manufacturers to essay its use. The result has been a sufficient 
amount of mining operations in the form of open pits somewhat to change 
’ the original aspect of the hill. Moreover, a large part of the boulders 
near the source of the train, and at various points in its length, have 
been gathered and shipped to distant parts. The illustrations (Plates 
I., If and III.) give the general form of the mass as it now appears. 
In its original aspect it had the regular arched shape which is common 
