2348. MINERALS FROM TRUMBULL, CONNECTICUT—SHANNON. 471 



gray, with large calcite grains in a finer ground mass, giving the 

 rock a porphyritic appearance. About 150 feet southeast of the 

 limekiln a trench has been dug some 75 feet on a quartz-topaz vein, 

 which is referred to as the Limekiln Vein in the following descrip- 

 tions. Numerous other shallow pits and trenches have been dug, 

 but those examined by the writer showed no minerals of unusual 

 interest. The minerals occurring in the vicinity of Long Hill are 

 described below: 



SCHEELITE. 



Previous writers have described the scheelite as nearly white in 

 color and occurring in quartz with epidote, hornblende, and mar- 

 casite, in the form of well-defined tetragonal pyramidal crystals an 

 inch or more in diameter, and as masses sometimes several pounds 

 in weight, loosely imbedded in the matrix. No scheelite was found 

 by the present writer. 



WOLFRAMITE. 



Wolframite at this locality occurred under the same conditions 

 as scheelite, being in all cases pseudomorphous after the lime tung- 

 state and preserving its crystal form. These specimens are no longer 

 obtainable at the locality. The pseudomorphs are said to have been 

 found only in portions of the ledge which were weathered and iron 

 stained. An excellent suite of these pseudomorphs is preserved in the 

 Brush collection of Yale University. 



TUNGSTITE. 



Tungstic ocher occurred rarely as a thin yellow coating on quartz. 

 It was not abundant and is not now obtainable. 



MARCASITE. 



Marcasite, more or less weathered, is abundant in the upper mine 

 opening and in the north end of the lower opening. Here it occurs 

 in granular masses and also as internally fibrous mammillary crusts 

 a half inch in thickness on the walls of narrow open cracks in the 

 lower limestone bed. It is very prone to oxidize under the action 

 of the weather, and most of the abundant ocherous limonite stains 

 present have come from its alteration. 



SPHALERITE, 



A brilliant coarse granular and very black sphalerite occurs in ag- 

 gregates up to 3 inches in diameter in the narrow quartz-topaz veins 

 in the main pit, especially where these veins cut the marcasite layer 

 at the north end of the pit. The sphalerite, which upon weathering 

 assumes an iridescent tarnish, occurs in vitreous grayish quartz asso- 

 ciated with margarodite, margarite, and topaz. The sphalerite was 



