NOTE M - On the Age of Strata, as inferred from the Rings of Trees embedded in them

Summary

The indelible records of past events which are preserved within the solid substance of our globe, may be in some measure understood without that refined analysis on which their complete knowledge depends. The remains of vegetation, and of animal life, embedded in their coeval rocks, attest the existence of other times; and as science and the arts advance, we shall be enabled to read the minuter details of their living history. The object of the present note is to suggest to the reader a line of inquiry, by which we may still trace some small portion of the history of the past in the fossil woods which occur in so many of our strata.

It is well known that dicotyledonous trees increase in size by the deposition of an additional layer annually between the wood and the bark, and that a transverse section of such trees presents the appearance of a series of nearly concentric irregular rings, the number of which indicates the age of the tree. The relative thickness of these rings depends on the more or less flourishing state of the plant during the years in which they were formed. Each ring may, in some trees, be observed to be subdivided into others, thus indicating successive periods of the same year during which its vegetation was advanced or checked.