inner courtyard from which access was obtained to a row of chambers, varying in number, placed against the back wall. The building of this type at Newstead measured 131 feet in length by 104 feet in breadth, and is the largest of the kind we know in Britain. The Principia at Chesters approaches

it in size, measuring 123 feet long by 97 feet broad. Birrens, on the other hand, is only 70 feet long by 8o feet broad, and Gellygaer 80 feet by 69 feet. To this main building, which may be taken as representing the normal plan in Britain, there was added, at Newstead, a long entrance hall or portico extending across the Via Principalis in front of the building and measuring

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