chroic
like bastite, and seems to be a new variety of that mineral. (It is
seen only in the Kentucky rock.) Dr. Eosenbusch suggested to me that it
resembled the 'aerinite' of Lasaulx,1 also a product of
alteration. It will be more fully treated under the description of
bastite. The unÂusually perfect cleavage in the olivine is particularly
well developed near the edges, where the fibrous substance is formed.
This alteration is at the edges of otherwise
1 Neues Jahrb. 1876, p. 352; Bull. Soc. Min, de France, i. 1878, p. 125.