MUSEUxM 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 

 tlie glacial trail, the pebbles within its belt are extremely numerous, 

 constituting for some miles of distance a considerable percentage of these 

 drift materials. Therefore tliese 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 nnlooked 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 obsei-ved 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. Tlie 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., II 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 



