136 SPARKS FROM A GEOLOGIST'S HAMMER. 



that mountains which once reared their heads above the 

 clouds have been gnawed down by the tooth of time; and 

 that whole continents, built on foundations of granite, 

 once clothed with somber forests, and swarming with the 

 humble populations of a primeval time, have been literally 

 eaten up by the sea. Lift up your eyes and behold the 

 proofs. Look around you and contemplate the fragments 

 of a meal which consisted of mountains and cubic miles 

 of solid land. 



We turn again to a survey of some of the facts. There 

 is a region on the American continent which we style the 

 Archaean. It lies north of the St. Lawrence and the great 

 lakes. It is composed of the oldest rocks known to geology. 

 There they come to the surface; but we know that they 

 continue underneath formations of more recent date, both 

 on the north and the south. They spread under us every- 

 where. These rocks are hard and crystalline. They em- 

 brace granites and syenites and diorites; but they are all 

 sedimentary. They are not a part of the primitive, fire- 

 formed crust of the earth; they are fragmental. Some 

 older formation some older land has been worn down 

 to supply the material for these vast beds of detritus. 

 But I said these are the oldest rocks known. The oldest 

 known rocks are composed of worked-over material. The 

 oldest known rocks are built of the ruins of some wasted 

 land, on which human eyes have never rested. Where 

 lay the lands whose slowly crumbling shores yielded the 

 quartz and the granite to build up the Laurentide hills? 

 When these hills first rose, slime-covered, from the uni- 

 versal sea, only a waste of waters surrounded them. We 

 are certain, at least, that for many geologic periods the 

 ocean expanse, on all sides, was unbroken. Land there 



