A few words
of explanation are necessary in order to indicate my connection with
this book and what has or has not been attempted in preparing it for
publication. Shortly after the death of Professor Carvill Lewis in July
1888, in accordance with directions given during his last illness, the
manuscripts of his two papers on the diamond-bearing rocks of
Kimberley, communicated to the British Association at the meetings in
1886 and 1887 respectively, together with the specimens on which he had
worked and a number of miscellaneous notes, were given by Mrs. Lewis to
Professor G. H. Williams of the Johns-Hopkins University, who had
kindly promised to carry out his late friend's desires by preparing the
incomplete material for publication, as soon as his other duties and
engagements permitted. But the pressure of these was so great that an
opportunity had not been found when he too was taken away from this
world by the same disease (typhoid fever) which had proved fatal to
Professor Lewis, As I have been for many years a student of the
structure and history of olivine rocks and serpentines, I had felt
great interest in the papers to which I had listened at Birmingham and
Manchester, and thought it would be most unfortunate if the numerous
careful and minute observations which they
