53 



colored and more crystalline. This is, accurately speak- 

 ing, shivered to pieces by eruptive forces, Avhich have at 

 the same time filled the numberless crevices and hollows 

 between the fragments with one form of the igneous gran- 

 ite alluded to. This is always lighter colored, and often 

 reddish on account of its flesh-colored feldspar. There 

 are perhaps eight or ten square miles of this broken rock, 

 and yet in many places, if the injected granite were 

 removed, every dissevered piece of the dark granite 

 would fit together edge to edge like a consolidated block- 



O O c 



puzzle. 



It is only fitting here to say that the successful prose- 

 cution of the survey must be largely attributed to the en- 

 couragement and assistance of Dr. Sterry Hunt. The 

 communication made by this gentleman at the Salem 

 meeting of the American Association, upon the rocks of 

 this region, incited Mr. Bicknell to renew his formerly 

 unsuccessful search at Newburvport for the Eozoon. The 

 subsequent discovery of this fossil and the beginning of 

 the field work were the indirect consequences of this and 

 of his subsequent visits. The President and Directors of 

 the Eastern Railroad have also substantially assisted in 

 the progress of the survey and I have personally received 

 aid from others to Avhom my indebtedness will be duly 

 acknowledged in more formal publications. 



Note by Dr. T. Sterry Hunt. In a communication 

 to the Boston Natural History Society on the 19th of 

 October last, and subsequently in' the American Journal 

 of Science for February and March, 1871 (pages 84 and 

 182), I have expressed the opinion that the porphyries 

 of the eastern coast of Massachusetts, are stratified rocks, 

 belonging together with their associated diorites and 

 slates (greenstones, chloritic and epidotic rocks), to the 



