56 PATTERSON v. M'CAUSLAND.—3 BLAND.

But Patterson and Ellicott, to impeach the testimony of the wit-
nesses produced by M'Causland to prove the call for the marked
black oak, the going to which brings those two elder tracts
together, and closes the access to M'Causland's First Attempt,
shew that the black oak, of which the witnesses speak, is that
which is designated as a marked black oak in the certificate of
Jolly's First Attempt, bearing date in the year 1791; and that in
a block, so cut out of that tree as to include the whole of the only
chop mark upon it, there appears to have been added, by natural
growth, only twelve concentric layers of wood outside of, and since
the chop mark was made. They exhibited this block to the Court
as evidence; alleging, that according to the regular and uniform
course of nature, there is in all trees one such concentric layer
of wood always formed every year. And, therefore, they con-
tended, that the irresistible presumption was, that the black oak,
shewn by those witnesses, upon the resurvey, could not have re-
ceived the chop mark so long ago as the year 1791, when the tract
called Jolly's First Attempt was laid out; and consequently, could
not be the marked black oak called for in the certificate of that
tract; and that call being thus clearly disproved, the lines of that
tract must, so far, be laid down by course and distance; and in
that mode of locating it, there would be left a considerable space
of vacancy along which the resurvey of Litten's Fancy might be
extended, as it had been, so as to take in the whole of the tract
called M'Causland's First Attempt.

BLAND, C., 3d December, 1830.—This case standing * ready
71 for hearing, and the attorneys of the parties having been
fully heard, the proceedings were read and considered.

The evidence here relied on to contradict and discredit the tes-
timony of the witnesses who have been produced to prove the
marking of this black oak as a boundary, is founded on a pre-
sumption, derived from what is alleged to be the regular course of
nature in the growth of forest trees. I have met with no Instance,
in the books, in which proof of this kind had been received and
respected in a Court of justice.

A presumption is an inference as to the existence of a fact, not
actually known, arising from its usual or necessary connection with
others which are known. 1 Stark. Evid. 23. The whole force of
the presumptive evidence, here offered, rests, therefore, upon the
fact of the alleged regular and invariable course of nature in the
formation and growth of trees, being well known; or at least on its
being susceptible of, or having been clearly established by proof.
For, if the course of vegetation, in this particular, be irregular,
unknown, or on any account incapable of proof, then no inference
can be deduced from it worthy of any consideration whatever as
evidence. The point then to be here determined is, whether, in