ARCHAEAN SYSTEM AND ARCHEOZOIC ERA. 265 



Area. 1. These rocks cover the whole of Labrador, 

 nearly the whole of Canada (passing into New York in 

 the region of the Adirondacks), then extend northwest 

 probably to the Arctic regions. This, the greatest Ar- 

 chaean area in North America, forms a broad, open V, 

 inclosing in its arms Hudson Bay. 2. The next largest 

 urea is a broad space extending from New England to 

 Georgia, including the Blue Eidge and the eastern slope 

 of the Appalachian. 8. The axes of many of the great 

 mountain-ranges, such as the Colorado, Park, and Wah- 

 satch Ranges, and possibly the Sierra Nevada. 4. Some 

 small, isolated spots, one in Texas and one in Missouri. 

 In the map (page 272) these are represented by v 



Physical Geography. These being stratified rocks, 

 it is evident that the whole Archaean area was sea-bottom 

 at that time. Where, then, was the land from which 

 this debris was derived ? Of this we know nothing. 

 Some have thought that it was to the northeastward. 

 We shall see hereafter that the continent developed 

 southward and westward. 



Amount of Time. The Archaean rocks are of enor- 

 mous thickness, probably equal to all other subsequent 

 rocks put together. The amount of time represented is, 

 therefore, probably equal to all the rest of recorded his- 

 tory of the earth. And yet how meager the record ! It 

 is the same with the earliest human history. 



Life. Did any living thing exist at that time ? This 

 is a very important question, but we can not yet answer 

 it with absolute certainty. There are, however, some 

 good evidences of life : 1. Iron-ore is accumulated now, 

 and therefore probably also in earlier times, only by means 

 of decaying organic matter (page 89), and is, therefore, 

 justly regarded as a sign of life and a measure of its 

 quantity. 2. Graphite is regarded as the highest anthra- 

 citic condition of coal ; and coal is a positive sign of 

 organic matter, and therefore of the previous existence 



