ked their food,
and carried on their work, and--dwelt, in short."[58]

These two "green hillocks," and other structures of the same nature, are
shown in the accompanying diagrams[59] (Plates I.-XVI.), which explain
their formation better than any written description. It is enough here
to state that they are built of rough stone, without any mortar. "Though
the stone walls are very thick," says my authority (p. 62), "they are
covered on the outside with turf, which soon becomes grassy like the
land round about, and thus secures perfect wind and water tightness."
Sometimes they occur in groups, as those shown in Plate III.; of which
scene Captain Thomas justly remarks that "at first sight it may be taken
for a picture of a Hottentot village rather than a hamlet in the British
Isles."[60] Here there is little or no grassy covering outside, however;
and consequently none of the hillock-like effect. But this is very well
shown in Plates VI. and VIII. Of the "agglomeration of beehives"
pictured in the latter, Sir Arthur Mitchell observes:--"It has several
entrances, and would accommodate many families, who might be spoken of
as living in one mound, rather than under one roof" (_op. cit._ pp.
64-5). Of another such dwelling, now ruined, he says that it could have
accommodated "from forty to fifty people."

This last, however (Plates XI. and XII.), represents another variety of
earth-house, the chambered mound or beehive, with an underground gallery
leading to it. Of this kind two examples are here shown. And in Plates
I. and XIII. will be seen specimens of wholly subterranean structures.
It is difficult, and indeed hardly necessary, to distinguish between one
variety and another of what is practically the same kind of building;
but to this last class the term "earth-house" is most frequently
accorded in Scotland. In the broader dialect it is "yird-house" or
"eirde-house," which at once recalls the form "jord-hus" in the saga
which tells of Leif's adventure underground in Ireland. The term _weem_
is also applied to these places in Scotland. This is merely a quickened
pronunciation of the Gaelic _uam_ (or _uamh_), a cave; and it reminds
one that, both in Gaelic and in English, the word "cave" is by no means
restricted to a _natural_ cavity. Indeed, one of the two artificial
structures under consideration is known as _Uamh Sgalabhad_, "the _cave_
of Sgalabhad." Another old Gaelic name for those underground galleries
is "_tu