THE BEGINNING OF LIFE
There is, perhaps, no other chapter in the chronicle of the earth
that we approach with so lively an interest as the chapter which
should record the first appearance of life. Unfortunately, as far
as the authentic memorials of the past go, no other chapter is so
impenetrably obscure as this. The reason is simple. It is a
familiar saying that life has written its own record, the
long-drawn record of its dynasties and its deaths, in the rocks.
But there were millions of years during which life had not yet
learned to write its record, and further millions of years the
record of which has been irremediably destroyed. The first volume
of the geological chronicle of the earth is the mass of the
Archaean (or "primitive") rocks. What the actual magnitude of
that volume, and the span of time it covers, may be, no geologist
can say. The Archaean rocks still solidly underlie the lowest
depth he has ever reached. It is computed, however, that these
rocks, as far as they are known to us, have a total depth of
nearly ten miles, and seem therefore to represent at least half
the story of the earth from the time when it rounded into a
globe, or cooled sufficiently to endure the presence of oceans.
Pages:
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108