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1885.] NEW YORK ACADEMY OF SCIENCES. 41 



Monarchies, where the spikes are represented as plain, and in- 

 serted in an iron ball. 



When the British evacuated Boston, they scattered great 

 numbers of "crows-feet" on "the Neck" and in the streets. 



At the battle of Arbela (B. C. 331), Darius Codomaunus had 

 them strewed over the ground in anticipation of an attack from 

 the Greek Cavalry. 



They were called Triholos by the Greeks, and Tribulus by 

 the Romans. 



The Scots used them at the battle of Bannockburn, in the 

 year 1314. They are not now employed. 



Mk. B. B. Chamberlin read a paper, entitled : 



NOTES ON MINERALS FROM THE FRENCH CREEK MINES, CHESTER CO., 



PENN. 



(Illustrated with Specimens.) 



The deposits of magnetic u-on ore in the northern portion of 

 Chester County, Pa., have attracted considerable attention from 

 mineralogists, especially within the last two years. 



The French Creek Mine, lately visited hy the writer, is 

 situated near the village of St. Peters, at the terminus of a 

 branch of the Wilmington and Delaware Railroad. 



The mine is located near the summit of a hill, over the 

 slopes of which huge blocks of trap- rock are scattered in wild 

 confusion. At this point, the Primitive and Triassic forma- 

 tions are in proximity, intersected by a narrow trap-dyke. 



The first excavations were made for copper ore, 1>ut as little 

 but the sulphuret of this mineral appeared, a new enterprise 

 was inauo-urated — that of minins' for mag-netic iron ore, which 

 was found to exist in quantity warranting promise of great 

 success. The supply has reached the amount of 15,000 tons 

 per annum. 



The mineral collector finds here ample supplies of the mag- 

 netic iron in octohedral crystals of a brilliant lustre. In com- 

 bination with Pyrite and Chalcopyrite, the specimens are of 

 much beauty. 



The Pyrite presents the usual octohedral forms of splendent 

 crystals, many of which are finely modified and are occasionally 



