GEOLOGY AND MINERALOGY OF NEWBURY. 



BY B. F. MCDANIEL. 



The geology of Newbury is that of the Huronian Sys- 

 tem of the Eozoic period, that is, the period of earliest 

 life. The rocks of this system overlie those of the Azoic 

 period, and, until recently, were held to be non-fossilif- 

 erous. Biit the discovery of the Eozöon Canadense in 

 the Laurentian limestones of Canada and here in New- 

 bury moved far back the palaeontological horizon. With 

 the exception of small areas of palaBozoic rocks in Quincy 

 and Braintree, the Huronian system forms the main part 

 of the coast from the New Hampshire line to Plymouth. 

 In great part it is drift-covered. 



The rocks in sight show great disturbance and meta- 

 morphism. In some localities the evidences of these 

 changes are of the most striking character. Their condi- 

 tion is simply chaotic. 



The stratified portions have usually a northeast by 

 Southwest strike, and the unstratified and intruded mem- 

 bers of the series show a parallelism with the strike of 

 the stratified rocks, Avhich usually dip sharply to the 

 northwest. 



The Huronian system in eastern Massachusetts is chiefly 

 made up of the following rocks ; 



1. Granite (hornblendic and binary). 



2. Feisite (petrosilex of some authors). 



3. Diorite (unstratifed and chiefly exotic). 



4. Hornblendic gneiss, stratified diorite. 



5. Limestone. 



(103) 



