water from the west side of this block, as also the water from the Courtyard of the Principia. Another large drain was traced between Blocks XVII and XVIII running westwards through the Retentura. It passed beneath the reducing wall, where its structure was well preserved and where it had a depth of eighteen inches and a width of fifteen inches (Plate VII., Fig. 2). All of these drains were probably brought together and carried into the inner ditch on the west front, passing beneath the wall of the fort in a strongly built channel, having an opening two feet eight inches high by two feet broad (Plate VI., Fig. 2). With the exception of a drain running along the south side of the street near the east gate no drains were noted in the Praetentura. The ground here was higher and less liable to be flooded.
General Condition of the Buildings
Before dealing more particularly with the various buildings, it may be noted that, throughout the excavations, the remains of their stone-work were so scanty as to make it almost impossible to recover any of their details. Long centuries of cultivation and systematic quarrying had well nigh brought about their utter destruction. Walls were in most cases reduced to foundations. Hardly a doorway of any kind could be traced. Search for such masonry as may be seen in situ at Chesters and Housesteads, or in the impressive buildings recently exposed at Corbridge on Tyne, was vain. As a matter of fact, the only building within the fort which was laid bare in anything like its entirety was the Principia. The rest were merely outlined by following the walls, diagonal trenches being cut across any chambers which were discovered. This method has many drawbacks, and it should be avoided wherever circumstances permit of more thorough exploration. But the cost involved in removing the earth from the large area to be dealt with at Newstead made it impracticable to proceed otherwise.
The Principia
Of the various buildings which once occupied the area of the smaller Roman forts the Principia is the one of which excavation has recovered the greatest number of plans. That this is so is probably due to the fact that it was usually erected in stone. And it is as common a feature of the forts in Germany as of those in Britain. Nearly all of the plans conform to a general pattern, although there are variations in detail. The best specimens of the building as we find it in Britain are at Birrens, Housesteads, and Gellygaer. In all of these we have an outer courtyard surrounded by pillars, which was entered from the Via Principalis, and also an
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