1920.] NATURAL SCIENCES OF PHILADELPHIA. 359 



Unless this very slight character is accepted as sufficient, there is 

 nothing visible on the specimen to justify classing it as a chondrite. 

 On the broken face was a partly separated spall, a few millimeters 

 in diameter, which was removed, and from it a rather unsatisfactory 

 section prepared for microscopical examination. This section, 

 which would have been entirely too small to represent the meteorite 

 generally, had not the preliminary examination demonstrated a 

 remarkable degree of uniformity throughout the stone, shows a fine 

 granular texture made up of minute angular fragments of enstatite 

 and olivine, mostly too small for satisfactory determination. There 

 are two or three individuals inthesection which exceed .5mm in length, 

 but many less than .1 mm. A portion of one of the veins passes 

 through the section. It is black and opaque, and about .02 mm. 

 thick throughout most of its length, with several lenticular thicken- 

 ings, which generally include grains of metal and sulphides. Num- 

 erous small grains of metal are likewise scattered among the silicates, 

 together with even more plentiful, but smaller, grains of troilite or 

 pyrrhotite. A few opaque black grains, with some' indications of 

 crystal faces, are probably chromite. 



The most interesting feature exhibited by the section, is the 

 presence of not inconsiderable quantities of a glassy transparent 

 substance that may be identified as maskelynite, resembling in all 

 respects that of Alfianello. This mineral, which has a refractive 

 index so close to that of balsam that the ground surfaces appear as 

 if perfectly polished, generally occupies irregular spaces between 

 the magnesian silicates and sometimes holds small grains of the 

 latter as inclusions, but in one case takes the form of a nearly cir- 

 cular grain suggesting a rounded crystal, with its interior clouded 

 with numerous small inclusions. When examined in ordinary light 

 under high powers, using good objectives and carefully adjusted 

 illumination, there occasionally appear in it systems of fine parallel 

 lamina, sometimes intersecting. On applying polarized light, such 

 spaces generally show faint double refraction, somewhat similar to 

 that of leucite. Not the comparatively strong double refraction of 

 large leucite crystals, but more closely resembling that of the small 

 crystals in fine grained Vesuvian lavas, which likewise sometimes 

 show similar parallel laminations with ordinary light. These lami- 

 nations might be interpreted as indicating incipient polysynthetic 

 twinning in a feldspathic material, but the resemblance shown by 

 all the characters of maskelynite to those of leucite, seems to furnish 

 some justification for Groth's opinion that the two minerals are 

 closely related. 



