vestigating
the history of such stones as he could trace. His conclusions are to
be published in a final memoir on the " Genesis of the Diamond," the
completion and editing of which has been undertaken, since his death,
by his friend and associate, Prof. George H. Williams, of the Johns
Hopkins University. A moderate number of well-authenticated diamonds
have been found in Georgia and in North Carolina, a very few are
reported from South Carolina, and one or two are known from southern
Virginia. These are all apparently derived from the detritus of the
crystalline metamorphic rocks that extend through these States as the
eastern ranges of the Appalachian system. Of these, the great
continuous Blue Ridge is, of course, the leading member ; eastward of
it lies the so-called Atlantic or Tidewater gneiss, by many regarded of
later age; and another belt, perhaps distinct, extends from Richmond,
Va., to the vicinity of Raleigh, N. C. It is much to be regretted that
the geology of these crystalline belts is thus far so little known. At
some points they appear to be well distinguished, while at others they
merge into one another and have not been clearly defined. The names
Laurentian, Hur-onian, Montalban, and Cambrian are variously applied to
different portions of them by different geologists. The Blue Ridge
proper is generally admitted to be chiefly true Laurentian ; and it is
certain that Cambrian beds appear at some points in the area. The
remarkable itacolumite rock, popularly associated with the occurrence
of diamonds, is found at many points on the flanks of the Blue Ridge,
but its geological age is not yet clearly established.
Beginning
with the account of the one well-known Virginia diamond, we shall pass
on southward, taking up the States in order. The Dewey diamond (see
Colored Plate No. i), was found at Manchester, Va., in 1855, and John
H. Tyler, Sr., of Richmond, Va., who was the first to see it, says : "
This diamond was found just opposite Richmond, by a laborer engaged in
grading one of the streets. It was brought to me to ascertain its
character and value. I pronounced it at once a valuable diamond, and
recommended the finder to keep it carefully and to see me about it
again. I did not know his name, and have not seen him since, but
afterwards learned that he sold it." The first record that we have of
