110 ARCHITECTURE. 
standing the usual width of a door apart. These stones, as well as all those 
which serve to support the upper slabs, are about 7 feet high, and their 
thickness varies from 7 inches to 1 foot 9 inches. The exterior breadth of 
the monument is nearly 15 feet, and the long sides are each composed of 
four stones, together about 52 feet in length. In the rear a single stone 21 
feet long, extending far beyond both side walls, forms the end. All the 
stones, excepting the two front ones, which form the door and stand per- 
pendicularly, are inclined inwards at"€he top. The ceiling consists of four 
stones, the largest of which is 22 feet long, 19 feet broad, and 3 feet thick. 
This slab is rent lengthwise, and is supported by an upright stone in the 
centre. Near Essé, a place not far from Rennes, is a similar grotto, which 
is more than 57 feet long and is divided into two chambers. J/g. 11 repre- 
sents the exterior view. Of the two chambers one is much the smaller and 
serves as a kind of vestibule, and is about 133 feet long and 8 feet broad, 
entirely open in front and lying towards the south-east. A passage between 
two stones leads into the chief grotto, which is broader than the first room, 
being 11 feet in front and 12 in the rear. On one of the walls, which is 
only a continuation of the wall of the first room, the stones project on the 
inside, forming as it were small chapels. The rear wall of the grotto con- 
sists of a single stone, and the ceiling of nine slabs, some of which are six 
feet thick. 
Near Tours is a similar monument called the Grotte des Fées, and repre- 
sented in jig. 12. The entrance is towards the west, and the grotto is 
inclosed by 12 rough stones. One fourth of its length is partitioned off by 
an upright stone, leaving only a passage or door free, and thus a kind of 
vestibule is formed. The top consists of three stones, the middle one 
of which is 6 feet thick, that is twice as thick as the other two. The whole 
length of the monument is 224 feet, its breadth 11 feet, and its height inside 
7% and on the outside on the centre top slab 133 feet. Although rough, the 
stones are more carefully joined than was generally the case with such 
monuments. There are similar grottoes in France and England; for 
instance, near Locmariaquer, near Ville-Genvin, and upon the island of 
Anglesea ; also in the province of Minster in Prussia. 
A very peculiar monument, somewhat resembling the covered ways, 
is the double dolmen in a wood upon the island of Anglesea (pl. 24, fig. 4). 
Two slightly inclined dolmen stand close behind each other, one resting upon 
four, the other upon three supports. The top of the larger is about 14 feet 
long, 12 feet broad, and 24 feet thick. The largest supporting stones are 
about 5 feet high. There is also a very rare monument in the department 
of Morbihan, bearing the same relation to the covered ways as the half dol- 
men to the dolmen. It consists (fig. 9) of a row of upright stones, against 
which another row leans obliquely, and the monument thus appears like 
a row of half dolmen placed closely together. 
Much has been said of the object of these covered ways, and it has not 
yet been explained. The simplest and most natural idea seems to be, that 
the piatforms of these ways, like that of the dolmen, were devoted to sacri- 
fices celebrated in the presence of the people, while the covered room under- 
110 
