MINERALS OF MARYLAND. Ill 



Liihoniarge, occuvs at 'Soldier's Delight' and Barehills; liiat 

 of the former locality has all the variety of colour of the Coop- 

 town talc. 



Asbestus, of the flexible varieties, most abounds at the Bare- 

 hills, while the ligniform occurs principally at Cooptown. 



Hydrosilicates of tnaguesia occur at the different localities 

 and furnish a material for the production of a large amount of 

 magnesia and its salts. The proportions of the constituents of 

 this mineral vary considerably. And as its external appear- 

 ance is somewhat variable, some of the mineralogists of the 

 present day, who cannot be satisfied unless each mineral has at 

 least a score of names, have gratified themselves by favouring 

 the scientific world with a goodly number of new names for this 

 substance. It seems almost to graduate into opal on the one 

 hand, and hydrate of niaguesia on the other. Both in appear- 

 ance and composition ; in fact se7ni opal and the pure Ity- 

 drate of tnagnesia exist in the serpentine formation. 



Hornhlend occurs at the Barehills in radiated masses in 

 felspar, accompanied by radiated tremolite of a gray colour. 



Tourmaline^ in olive coloured crystals of a large size, exists 

 at Cooptown, accompanied by a white opaque substance, in 

 small crystals, whose nature has not been determined. 



Pitchstone occurs in a thin seam at Barehills. 



Aveiiturine felspar and beryl are noticed by Dr. Hayden,* 

 on the eastern border of the serpentine at Barehills. 



A dendrilic appearance in the fissures of the magnesian 

 minerals is very common, and beautiful specimens occur at 

 the Barehills ; the dendrites are usually oxide of man- 

 ganese. 



Ferroxide of chrome occurs throughout the serpentine. It 

 was first found at the Barehills, in quantities sufficient for 

 manufacturing purposes. But for several years past the ser- 

 pentine of Harford counly, as well as that on the northern 

 border of Cecil county and extending into Pennsylvania, yield 

 the largest amount. 



Green oxide of chrome. At the last mentioned locality, a 

 mineral of a beautiful bright green colour, compact, and liaving 

 a smooth waxy aspect, occurs in very small quantities and has 



* Silliman's Journal, vol. 2-1, pp. 357, 358. 



