They were transported, perhaps, from the Azoic area near Lake Superior.
Thus the azoic group is crystalliferous, or crystal-bearing.
That land belongs to the Azoic period, and contains no trace of life.
In the European ocean of the Azoic epoch we find five islands of considerable size.
The oldest lands of North America were built up, as in Europe, of azoic rocks, and were grouped chiefly in the north.
Distinct fossils have not been found, all that ever existed in the azoic rocks having been obliterated.
Even in the Azoic or Archozoic Age there are traces in ice-worn rocks and the like of periods of intense cold.
Geologists have divided a few years of the worlds history into periods, reaching from the azoic rocks to the soil of our time.
The tertiary formation is followed by an azoic formation of gneiss, mica slate, and phylada with large intrusions of granite.
Now, most of these Canadian rivers are Azoic in character; hence their grim and formidable beauty.