16 Field Columbian Museum — Geology, Vol. III. 



or more component lamellae joined end to end. The ends 

 of these component lamellae are usually rounded. The lamellae 

 are frequently crossed by fractures which usually run normal to 

 the length, but are occasionally more inclined. 



Between chondri with a structure of the above character and 

 those which are porphyritic there seem to be all gradations. The 

 stages are: i. Chondri in which the lamellae are wider and fewer in 

 number; and 2'. Wide lamellae extending only partially across the 

 chondrus. If the writer is correct in this observation, it is easy to 

 see that differences of extinction do not necessarily prove a poly- 

 somatic origin for a chondrus. The lamellae of each chondrus of the 

 types figured above are doubtless of a single generation, though 

 differently oriented. So the crystals of a single chondrus though 

 differently oriented may be of a single generation. Another arrange- 

 ment of chrysolite and glass lamellae which was seen in addition 

 to those noted above was an eccentrically radial one. These la- 

 mellae are wider than those which are parallel. In this case the 

 lamellae are wedge-shaped, and are enclosed in a glass so dark 

 as to be opaque. In the porphyritic chrysolite chondri the crystals 

 were for the most part uniform in size. In one chondrus, however, 

 a large crystal with rectangular outline was seen to occupy the 

 center with smaller ones grouped concentrically about it. In another 

 large chondrus a smaller one was enclosed. In addition to its 

 occurrence in chondri chrysolite is to be found in individual crystals 

 scattered through the mass of the meteorite. These crystals usually 

 do not appear to be formed in place, but to be fragments consolidated 

 with the chondri. They show no signs of decomposition or wear, and 

 are free from inclusions. In outline they are rectangular to polygonal, 

 and in length measure from .2 to .5 mm. 



The enstatite chondri show little variation from the usual fan- 

 shaped forms. The individual fibers in these forms, however, are 

 usually much less distinct than the individual lamellae of the chrys- 

 olite chondri. In one enstatite chondrus an appearance of a system 

 of fibers crossing the main system at right angles was found on 

 study with a higher power to be due to a textural change across 

 the fibers along these lines. Such a change suggests strain. Large 

 individual crystals of enstatite occur, the largest noted being 

 lath-shaped and having a length of 4 mm. and a width of 2 mm. 

 This is truly a remarkable size when compared with that of the 

 general constituents of the meteorite. The outlines of this crystal 

 were irregular, yet it was sharply separated from the surround- 



