spherical concretions composed of hard calcareous sandstone, containing a
few shells, occurring in a bed of sandstone) were 4 feet in diameter, and
in a horizontal line 9 feet apart, showing that the calcareous matter must
have been drawn to the centres of attraction from a distance of four feet
and a half on both sides" ("Geological Observations on S. America," page
113).) I have not examined carefully, from not soon enough seeing all the
difficulties; but I believe, from what I have seen, that the folia in the
metamorphic schists (I do not here refer to the so-called beds) are not of
great length, but thin out, and are succeeded by others; and the notion I
have of the molecular movements is shown in the indistinct sketch herewith
sent [Figure 6]. The quartz of the strata might here move into the
position of the folia without much more movement of molecules than in the
formation of concretions. I further suspect in such cases as this, when
there is a great original abundance of quartz, that great branching
contemporaneous veins of segregation (as sometimes called) of quartz would
be formed. I can only thus understand the relation which exists between
the distorted foliation (not appearing due to injection) and the presence
of such great veins.

I believe some gneiss, as the gneiss-granite of Humboldt, has been as fluid
as granite, but I do not believe that this is usually the case, from the
frequent alternations of glossy clay and chlorite slates, which we cannot
suppose to have been melted.

I am far from wishing to doubt that true sedimentary strata have been
converted into metamorphic schists: all I can say is, that in the three or
four great regions, where I could ascertain the relations of the
metamorphic schists to the neighbouring cleaved rocks, it was impossible
(as it appeared to me) to admit that the foliation was due to aqueous
deposition. Now that you intend agitating the subject, it will soon be