The bricks found in the walls of this structure vary in size both superficially as well as in thickness; this we find to be the case in most Roman work, for no certain scale of dimensions appears to have been followed in the making of their bricks: perhaps the average size may be stated to be 15 inches long by 10 inches wide, and 212 inches thick, but the thickness of these bricks or tiles vary from 34 of an inch to 3 inches.
What is called herring-bone work, is by itself no criterion of any particular era; whether it may be found in any of the rude masses of ancient British masonry, is a question still to be solved. It is found in Roman, Anglo-Saxon, and Anglo- Norman masonry. It has also been met with in masonry of so late a period as the fourteenth century.
Though this subject has been here treated of in a very cursory and superficial manner, and nothing has been stated but what is probably well known to many, the object is rather to call attention to the investigation of the remains of early masonry wherever they exist, not merely with regard to construction, though that is and ought to be a primary consideration, but also with regard to external appearance, so as to ascertain, if possible, whether the differences between the masonry of Roman, Anglo-Saxon, and Anglo-Norman construction, are really such as will afford us any evident marks and positive rules of discrimination.
