MISCELLANEA. 



area of eight square miles, and distant about four miles from 

 the town, towards the N.E. The surrounding formation is 

 composed of a series of gneiss, mica, hornblende, and talcose 

 schists, associated with granite and a rock analogous to ser- 

 pentine, penetrated by dykes of basaltic greenstone. The 

 magnesite is chiefly found in the hornblende, in veins vary- 

 ing in thickness from a yard to a few lines. Its general 

 character in the mass is that of a hard white travertine ; its 

 colour varies from white to bufi ; its fracture is conchoidal, 

 and although softer than quartz, it is sometimes hard enough 

 to strike fire with steel. — Lieut. T. J, Newbold, 



On the Mines of Chromate of Iron in Southern 

 India. — These are situated in the neighbourhood of Salem? 

 where it is associated with magnesite, forming with it a com- 

 plete net work. The chromate sometimes runs in veins, 

 varying in width from nearly four feet to less than an inch, 

 but suddenly and irregularly contracting and expanding. In 

 other cases it is found in nodules inclosed in the magnesite, 

 the nodule in one instance weighing two tons. The veins 

 run more frequently along the sides than down the middle of 

 the veins of magnesite, though frequently they penetrate and 

 intersect them, — a fact indicative of their posterior origin. 

 A specimen yielded about 49 per cent, of chromic acid upon 

 analysis. — Lieut, ./. Newbold, 



Earthquake in Cornw^all. — It has been ascertained 

 that the effects of this earthquake were greatest near the 

 edge of the granite mass, which extends from the N.E. to the 

 S.W., from Carn Marth to south of Penryn. Although it 

 was felt at Falmouth, Helston, and other places, which are on 

 the clay slate, yet all inquiries show that it diminished in 

 force rapidly as the distance from the granite increased.— 

 Proc. Polytechnic Society of Cornwall, 



