In this and most other stations, writes Hodgson, ‘there are found considerable quantities of limestone, having partly the character of stalagmite, and partly that of such cellular stone as forms about the mouths of petrifying wells. Some of it is in amorphous lumps; but the greatest part of it has been either sawn into rectangular pieces, or formed in a fluid state in moulds.’ They are probably artificial; at HABITANCUM, where this calcareous substance is abundant, it seems to have acquired its porosity by being mixed with straw. The use to which it has been applied is by no means obvious. Hodgson thought that it had been inserted in the side walls of the hypocausts, to allow heat to arise from below without smoke. This is doubtful. At HABITANCUM, the blocks, I am told, have been used as ordinary stones. In the construction of the Pharos at Dover, (where building stone is scarce) the calcareous composition has been largely used. Why it should have been employed at HABITANCUM, and other places, where free-stone is abundant, does not appear. [Sidenote: BORCOVICUS] The suburbs of BORCOVICUS have been very extensive, the ruins of them distinctly appearing on the east, south, and west sides of the station. A little to the south of it, and stretching westward, the ground has been thrown up in long terraced lines, a mode of cultivation much practised in Italy and in the east. Similar terraces, more feebly developed, appear at Bradley; I have seen them very distinctly marked on the banks of the Rede-water, Old Carlisle and other places. A well, cased with Roman masonry, is in front of the shepherd’s house, south of the station; a spring, yielding excellent water, is at the bottom of the same field; the Knag-burn washes the station on its eastern side, and there is ‘a fine well under the high basaltic cliff’ on which the northern wall of the station stands, ‘which is still well walled round,’ and has occasionally been used as a bath. None has been discovered within the station itself. _PLATE XI_ [Illustration: Broken Columns, Borcovicus] _PLATE XII_ [Illustration: Sculpted Figures, Borcovicus] _PLATE XIII_ [Illustration: Sculpted Figures, etc.] [Sidenote: ARCHITECTURAL REMAINS.] In the valley below is a small sandstone ridge, called Chapel-hill, from the idea that a temple stood upon it. Two fine altars have been found here.[108] The ruins that contained the Mithraic antiquities, to which reference will be made afterwards, stood a little to the west of this hill. All traces of the small, dark temple, where the horrid mysteries of the god were performed, are now nearly obliterated.