Editorial Comm.ent. Ill 
felclspathic magmas, and even quartz, magnetite, limestone, rock- 
salt, anhydrite and some ela3's and sands. To this he states there 
is no evidence in the lithological character of these rocks of their 
volcanic origin. And that the universality of their distribution 
and unity of characters, as well as the thoroughly' crystalline 
character of the gneiss, are incompatible with this idea. 
(3.) The me^amorpAic hypothesis would derive the primitive 
strata from the consolidation and the recrj'stallization of detrital 
plutonic rocks, or at least from rocks derived from the destruction 
of other older rocks, the debris from which had been laid 
down in the bottom of the sea as sediments. The enormous thick- 
ness of the primitive strata, at least 30,000 feet, and their world- 
wide extent renders it inconceivable that any older lands could 
have existed capable of furnishing this amount of material b}' any 
such process. Again the cr3-stalline condition of the gneiss is so 
perfect that it bears slight resemblance to any rock known to have 
been formed by such consolidation from sediments ; and all 
examples of reputed metamorphic rocks like those of the primitive 
strata, of secondar}* or tertiary age, have, on careful examination, 
been found to be based on wrong observation. 
( 4. ) The metasomatic h^-pothesis postulates the formation of vast 
deposits of limestone and their subsequent conversion into gneisses 
and schists by slow chemical replacement. This has for its basis 
the occasional observed association of some silicates with calcite 
and their substitution for it. The author regards this hypothesis 
as a gratuitous one, and says that it "would make as great a de- 
mand on our credulity as the metamorphic hypothesis itself."' 
(5.) 1\iQ chaotic hypothesis, of Werner, which supposes that 
all the materials of the cr\'stalline rocks were originally dissolved in 
a primeval sea, and were successively deposited in crj'stalline form 
from it, meets with insurmountable chemical difficulties, the chief 
of which is the inconceivableness of any conditions by which all 
these elements could have been held in solution by the ocean at 
any one time. This idea, successfully urged by Playfair and his 
followers, "contributed to the discredit which fell upon the AVer- 
nerian hypothesis." 
(6.) The theory of Daubree, the thermo-chaotic hypothesis, 
requires tliat the first oceanic waters be hot, and thus able to ex- 
ert a powerful solvent action upon the previpusly formed plutonic 
rocks of the primitive crust, transforming them into the present 
crystalline stratiform rocks. These waters were condensed upon 
