nm America and Hurope. 269 
remains, and transforming them into crystalline strata C- 
of its distribution, consist of uncrystalline siliceous, calcareous, 
and argillaceous fossiliferous sediments, and in another locality, 
d, 
effected in these strata, transformed into gneiss, hornblende- 
Schist or mica-schist, by what is vaguely designated as meta- 
morphism 
formations of stratiform crystalline feldspathic, hornblendic and 
micaceous rocks, which, in various parts of the world, have been 
alternately described as plutonic masses, and as metamorphosed 
rocks, pre-Cambrian or pre-Silurian in age, and that we know 
of no uncrystalline sediments which are their stratigraphical 
equivalents, 
Secondary origin of a great, and, by them, undefined portion of 
the crystalline stratiform rocks, while assigning to certain older 
(pre-Cambrian) erystalline rocks (of which they admit the ex- 
istence), either a neptunean or a plutonic origin.. Lhe « 
or plutonist school, while asserting the plutonic derivation of 
the greater part of the crystalline formations, accepts, to some 
Cover the ground held by the hitherto prevailing neptunean 
