398 Mr. PETRIE'S Inquiry into the Origin and 



marked externally by set-offs ; and in one instance, the Tower of Ardmore, by 

 bands or belts. With a single exception, however, they present no ornament 

 externally, except in their doorways and upper apertures. I allude to the 

 Round Tower of Devenish, which has a richly-sculptured band or cornice, 

 placed immediately beneath its conical roof, the whole of which is represented 

 in the preceding illustration. 



I must defer, however, an inquiry into the age of these sculptures, as lead- 

 ing to a digression that would be somewhat irrelevant here, and which I there- 

 fore reserve for the Third Part of this Work. 



Having premised thus much, relative to the general form and construction 

 of the Towers, I have next to notice their details ; and of these the doorways 

 are the most important, as enabling us to determine, by their architectural fea- 

 tures, the respective ages of the Towers to which they belong. 



The oldest Towers are obviously those constructed of spawled masonry and 



large hammered stones, and which present simple quadrangular and semicircular- 

 arched doorways, with sloping jambs, and little or no ornament, perfectly 



