riously
hued pigment, spread originally over the surface of the hard-cast wall,
were cut open, by the _denudation_ of the grindstone, into all manner of
fantastic forms, and seemed thrown into all sorts of strange
neighborhoods. The _map_ lacked merely the additional perplexity of a
few bold _faults_, with here and there a decided _dike_, in order to
render it on a small scale a sort of miniature transcript of the geology
of Banff; and I have very frequently found my thoughts reverting to it,
in connection with deposits of this broken character. On a rough
_hard-cast_ basis of granite I have laid down in imagination, as if by
way of priming, coat after coat of the primary rocks,--gneiss, and
stratified hornblend, and mica-schist, and quartz-rock, and day-slate;
and then, after breaking the coatings well up, and rubbing them well
down, and so spoiling and crumpling up the work as to make their
original order considerably a puzzle, I have begun anew to paint over
the rough surface with thick coatings of grauwacke and grauwacke-slate.
When this part of the operation was completed, I have again begun
to break up and grind down,--here letting a tract of grauwacke
sink into the broken primary,--there wearing it off the surface
altogether,--yonder elevating the original granitic _hard-cast_ till it
rose over all the coatings, Primary and Palaeozoic. And then I have begun
to paint yet a third time with thick Old Red Sandstone pigment; and yet
again to break up and wear down,--here to insert a tenon of the Old Red
deep into a mortise of the grauwacke, as at Gamrie,--there to dovetail
it into the clay-slate, as at Tomantoul,--yonder, after laying it across
the upturned quartz-rock, as at Cullen, to rub by much the greater part
of it away again, leaving but mere remainder-patches and fragments, to
mark where it had been. Lastly, if I had none of the superior Palaeozoic
or Secondary formations to deal with, I have brushed over the whole, by
way of finish, with the variously-derived coatings of the superficial
deposits; and thus, as I have said, I have often completed, in idea,
after the chance suggestion of the old painter's shop, my portable
models of the geology of disturbed districts like the Banffshire one.
The deposits of Moray are greatly less broken. Denudation has partially
worn them down; but they seem to have almost wholly escaped the previous
crumpling process.

CHAPTER IV.

Yellow-hued Houses Of Elgin--Geol