16 WORLD-MAKING 



rushing hither and thither in space, and it is almost equally 

 strange to imagine an intelligent Creator banging these bodies 

 about like billiard balls in order to make worlds. Still, in that 

 case we might imagine them not to be altogether aimless. 

 The question only becomes more complicated when with 

 Grove and Lockyer we try to reach back to an antecedent 

 condition, when there are neither solid masses nor nebulas, 

 but only an inconceivably tenuous and universally diffused 

 medium made up of an embryonic matter, which has not yet 

 even resolved itself into chemical elements. How this could 

 establish any motion within itself tending to aggregation in 

 masses, is quite inconceivable. To plodding geologists labori- 

 ously collecting facts and framing conclusions therefrom, such 

 flights of the mathematical mind seem like the wildest fan- 

 tasies of dreams. We are glad to turn from them to examine 

 those oldest rocks, which are to us the foundation stones of 

 the earth's crust. 



What do we know of the oldest and most primitive rocks ? 

 At this moment the question may be answered in many and 

 discordant ways ; yet the leading elements of the answer may 

 be given very simply. The oldest rock formation known to 

 geologists is the Lower Laurentian, the Fundamental Gneiss, 

 the Lewisian formation of Scotland, the Ottawa gneiss of 

 Canada, the lowest Archaean crystalline rocks. This forma- 

 tion, of enormous thickness, corresponds to what the older 

 geologists called the fundamental granite, a name not to be 

 scouted, for gneiss is only a stratified or laminated granite. 

 Perhaps the main fact in relation to this old rock is that it is a 

 gneiss ; that is, a rock at once bedded and crystalline, and 

 having for its dominant ingredient the mineral orthoclase, a 

 compound of silica, alumina and potash, in which are imbedded, 

 as in a paste, grains and crystals of quartz and hornblende. 

 We know very well from its texture and composition that it 

 cannot be a product of mere heat, and being a bedded rock 



