Thomas Burnet's Battleground of Time - Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time - page 57

secured his highest reputation for writing so brilliantly about the nature of
sedimentation) states that if strata of the second cycle do not differ internally
from beds of the first sequence, we shall possess no criterion for separating
the cycles except superposition, or the discovery of one set directly atop the
other. (And, as every geologist knows, our imperfect sedimentary record
rarely provides such direct evidence. We must be able to identify each cycle
from internal evidence, since we usually find rocks of only one cycle in any
single place.)
Steno then presents an internal standard using Burner's criterion of narrative.
He notes that strata of the first cycle contain no fossils (as products of the
original earth, before creation of life), while strata of the second cycle
include remains of plants and animals destroyed in the flood. "Thus we must
always come back to the fact that at the time when those strata [of the first
cycle] were being formed, the rest of the strata did not yet exist . . . All things
were covered by a fluid free from plants and animals, and other solids" (264).
Steno then invokes Burner's second criterion of history—the search for
vectors. He identifies two vectors as imparting a direction to time. First, each
new sequence of strata becomes more restricted in geographic extent since it
forms within the spaces left by collapsing crust of the last cycle. The first set
covered the entire earth (lower right of Figure 2.10); the second (lower left)
only fills the center. 10 Second, each successive collapse makes the earth's
surface more uneven (upper right of the first cycle compared with upper left
of the second), and we can know where we stand in time's arrow by
progressive departure from original smoothness: "The very surface of the
earth was less uneven, because nearer to its beginnings" (267).
We may, therefore, summarize the detailed similarities between Burnet and
Steno, two geological theories usually viewed not only
10. A modern geologist might object that such a progressive restriction would soon
reduce space for strata to nothing on an ancient earth. But Steno's earth was a young
planet, but two cycles old, and of limited potential duration.