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the other hand, quartz-rock occurs asfrequently in the coal formation, or inbeds which cover the chalk of the basin ofParis , as it does in the primitive districtsof Schichallion, Wicklow, and Conemara.

It is said in the Wernerian theory, that,after the formation of all other strata, animmense deluge suddenly occurred, and assuddenly retired, leaving, behind it, thosescattered hummocks of flotz-trap, whichhave, for some years, so greatly engaged theattention of geologists.

The proofs of this catastrophe, we areinformed, are to be found in the greatelevation which these rocks occasionallyattain ; in their broken stratification ; intheir unconformable posture; and in thenature of their materials.

But are trap-rocks really more elevatedthan others ? or their stratification morebroken ? It is time enough to considerinferences when we have established facts.

If the posture of trap is often unconfor-mable, so is that of granite, sienite, hom-

s