334 MURAL ARCHITECTURE 
former paper,* ) as indicating an acquaintance with 
the principle of the arch. But (setting aside the 
consideration already alluded to, as to the later 
date of this splendid building,) this idea appears 
to me a mistaken one. In the Treasury, as may 
be seen in the accompanying section,f given by 
Col. Leake himself, there is no keystone, pro- 
perly so called; the dome is terminated by a large 
stone, laid flat over the top of it, and the whole 
is kept in shape only by the weight of the super- 
incumbent earth. 
We may, therefore, I think, conclude, with as 
much confidence as can ever attend any conclusion 
respecting events so distant and obscure, that the 
Mural Architecture, which dates before the his- 
torical era, is referrible to three distinct styles, if 
not to distinct ages, and distinct people. 
I[.—Let us now proceed to consider the second 
question, viz.: “To whom these various fortifi- 
cations are to be attributed, and why they have 
received their present names ?” 
I. With regard to the amorphous style, of 
* Drawing VII. 
+ Drawing VIII. from Leake’s Morea. 
