NO. 1249. THE FELIX METEORITE— MERRILL. 195 
irresolvable material which forms the base. The enstatite chondrules 
are in some cases almost completeh' amorphous or cryptoerystalline. 
Fig. 2 of Plate XIY shows an impure nucleal mass surrounded by a clear 
transpai'ent border of the same material. In this case the chondrule 
extinguishes in polarized light as a unit, and the general appearance is 
remarkably like that of the quartz granules which have undergone 
secondary enlargement in sandstones.^ 
Many of the augites show poh'synthetic twinning such as was noted 
by Tschermak in the meteorites of Renazzo and Mezo Madras, as do 
also, according to the present writer's observation, those of the mete- 
orite of Warrenton, Warren County, Missouri. The banding is in some 
cases so regular and the colors so light that it was at first thought 
such might be in part plagioclase feldspars. The forms are, however, 
those of augite; the}" lack the pellucidity of feldspars, and, moreover, 
sections of the mineral showing no twinning bands always extinguish 
parallel with the vertical axes, while those showing twinning bands 
give extinctions as high as 39 degrees. There is, therefore, apparenth^ 
no doubt of their augitic nature. (See Plate XIV, fig. 2.) 
The most striking features of the stone are the extremely irregular, 
almost amorphous, areas shown in figs. 4, 5, and 6 of the same plate. 
These seem in a general waj' to resemble the amorphous chondrules 
described by Tschermak from the meteorite of Grosnaja and figured 
on Plate 20, fig. 2 of his MikrosJcojnsche Beschaffenheit der Meteoriten. 
They present, however, certain features such as suggest quite a differ- 
ent origin. 
In fig. 4 the outlines are very jagged, sharp crystal points projecting 
into the black ground mass and the whole made up of an extremely 
fine aggregate of nearly colorless, faintly polarizing granules inter- 
spersed with a few black spots. Fig. 5, on the other hand, is that of 
a nearh" amorphous or faintly cryptocrj'stalline mass. Fig. 6. which 
is one of the most striking, shows a distincth" crj^stalline border with 
an interior crj'stalline aggregate merging outward into cryptoerystal- 
line matter, as in the last case. The border, as shown when the body 
is viewed between cross nicols, belongs to a different and probabh'^ 
earlier stage of crj^stallization than the interior, and were the rock a 
terrestrial tuff, I think beyond question a majorit}' of petrographers 
would regard the entire aggregate as secondary, and as due to a deposit 
in a preexisting cavity through infiltration of solutions. The exact char- 
acter of the mineral comprising these areas can not with certaint}'^ be 
^ Tschermak described a like border in the chondrules of the meteorite of Gros- 
niija. He accounted for it by supposing it to be of secondary origin, a product of a 
second rise in temperature (accompanied it may be reducing vapors) not sufficient 
to produce fusion, but merely to bring about a structural modification in the super- 
ficial portions. (Min. u. Pet, Mittheil. I, 1878, p. 160.) 
