been in
sufficient quantity to form any extensive deposits. No doubt there was
some abrasion even of that first crust; but the more abundant source of
the earliest stratification is to be found in the submarine volcanoes
that poured their liquid streams into the first ocean. At what rate
these materials would be distributed and precipitated in regular strata
it is impossible to determine; but that volcanic materials were so
deposited in layers is evident from the relative position of the
earliest rocks. I have already spoken of the innumerable chimneys
perforating the Azoic beds, narrow outlets of Plutonic rock, protruding
through the earliest strata. Not only are such funnels filled with the
crystalline mass of granite that flowed through them in a liquid state,
but it has often poured over their sides, mingling with the stratified
beds around. In the present state of our knowledge, we can explain such
appearances only by supposing that the heated materials within the
earth's crust poured out frequently, meeting little resistance,--that
they then scattered and were precipitated in the ocean around, settling
in successive strata at its bottom,--that through such strata the heated
masses within continued to pour again and again, forming for themselves
the chimney-like outlets above mentioned.

Such, then, was the earliest American land,--a long, narrow island,
almost continental in its proportions, since it stretches from the
eastern borders of Canada nearly to the point where now the base of the
Rocky Mountains meets the plain of the Mississippi Valley. We may still
walk along its ridge and know that we tread upon the ancient granite
that first divided the waters into a northern and southern ocean; and if
our imaginations will carry us so far, we may look down toward its base
and fancy how the sea washed against this earliest shore of a lifeless
world. This is no romance, but the bald, simple truth; for the fact that
this granite band was lifted out of the waters so early in the history
of the world, and has not since been submerged, has, of course,
prevented any subsequent deposits from forming above it. And this is
true of all the northern part of the United States. It has been lifted
gradually, the beds deposited in one period being subsequently raised,
and forming a shore along which those of the succeeding one collected,
so that we have their whole sequence before us. In regions where all
the geological deposits,