470 
PETROLOGY: G. P. MERRILL 
Proc. N. a. S. 
SO large a number of chondrules of this type and the complete absence of 
such crust on the porphyritic and holocrystalline forms I have just been 
discussing are in themselves sufficient to enable one to safely differentiate 
between the two. 
The conclusions here reached are not quite so sweeping as those reached 
by Merrick in his humorous poem on the changeable colors of the chameleon, 
where he announces that "All are right, and all are wrong," but as is 
so frequently the case it seems to show that two or more of the opinions 
advanced were essentially correct and their apparent differences due to 
failure to recognize all of the facts I have here presented, and that of the 
many varietal forms of chondrules not all may have a similar origin. 
Before leaving this section of the subject, it may be well, however, to 
present reasons for the non-acceptance of certain of the views presented 
and enumerated. It will be noted that the conclusions I have reached, 
bear out for the varying types the ideas of both Sorby and Tscher- 
mak, those of the first mentioned supported by the experimental work of 
Rinne. With the views of Borgstrom and of Ramsay, so far as they bear 
upon the subject in the papers quoted, I am in agreement. With those 
of Hussak, so far as relates to the production of chondritic structures 
through the corrosive action of a nickel-iron-rich magma, I find no con- 
firmation. Not only is there little evidence that such a magma would 
corrode the silicates, but as in the case of meteorites of Brezina's Rockiky 
group (Admire and Eagle Station) there is direct evidence that it would 
not. Further than this, there is evidence that in my own opinion, tends 
to show that the iron of meteorites is altogether secondary and due to a 
reduction of some easily reducible compound like lawrencite, as I have 
elsewhere frequently stated. The expressed conclusions of Berwerth 
and Wahl are not sufficiently detailed to admit of close comparison other 
than to say that they both seem applicable to the chondrules of the en- 
crusted enstatite (kugel) type first mentioned, but not to the holocrys- 
talline and porphyritic forms. With reference to Dufrenoy's comparison 
of this structure to perlitic glass^^ it can only be said that while at first 
thought it might seem applicable to the glassy and half glassy porphyritic 
types, I find nothing whatever to sustain it and several facts which militate 
against it. First there are in no instances indications of perlitic cracks 
and second, in the terrestrial perlites, so far as my own observation 
goes, the cracks always pass around any existing phenocrysts, rather than 
through them as they must to have produced the forms shown in figure 8. 
It may be added that perlitic structure in terrestrial rocks is re- 
garded as due to shrinkage and limited to acidic magmas containing a 
considerable quantity of moisture. The structure is quite unknown in 
rocks as basic as are the meteorites. 
With reference to the spherulitic nature of the chondrules as advocated 
