24 THE HISTORY Book I. huts of reeds or turf. The former particularly were defigned to be the regular barracks of the garrifon, and muft therefore have been conftru&ed in the- fuperiour ftyle of Britilh architect- ure. They muft have been great round cabins built principally of timber upon foundations of ftone, and roofed with a Hoping covering of fkins or of reeds*. But the latter feem to have been conftru&ed in a fbmewhat different form, to have been not . rounded at all but nearly fquared, and to have contained about fixteen yards by twelve within. Such at leaft was the ground- , work of a building which was difcovered within the area of the Caftle-field in 1 766, and which was laid in a manner that clearly befpoke it to be Britifh. About half a yard below the furface of the ground was a layer of large irregular blocks, fome hewn from the quarry of Colly hurft, and others collected from the channel of the river. And below it were three layers of com- mon paving-ftones, which were not compacted together with mortar, but were bedded in the rude and primitive cement of clay. Such was the architecture of this fecret foundation, which was about two yards in breadth and about one in depth. And, as fuch, it appears to have been very antient. As fuch, it muft have been laid before the preparation of lime for the purpofes of building had been introduced among us, and confe- quently before the Siftuntii had been fubdued by the Romans. The knowledge of that preparation was firft communicated to .us by the Romans. This appears plainly from the prefent re- i mains of the Britifh buildings in the ifle of Anglefey in the Hebrides and in Wiltshire, which are all, like the more regular ftru&ures of the free Peruvians, conftru&ed entirely without the affiftance of mortar IO < And the fame fort of foundations has been actually difcovered about thofe huge obeli iks of the pri- maeval Britoas near Aldborough in Yorkfliire, which are fo fi- milar to the obelifks frequently ere&ed without their circular temples. A foot beneath the furface of the ground, a courfe chiefly of boulders has been found atone of them laid upon a bed of clay, four or fiye courfes of clay and boulders fpreading •fucceflively beneath it^and the whole rude ground- work regularly buttreffing
