Closely associated with terraced cultivation is the custom of erecting megalithic monuments. The erectors of the most numerous monoliths are the tribes practising terraced cultivation, though Kacha Nagas (Lyengmei) and Kabuis put up little dolmens and occasional monoliths, while the Lhotas and Rengmas proper, also having no terraced cultivation, yet erect monoliths and alignments of monoliths in all their villages. North and east of the two latter tribes, however, few Nagas seem to put up either, and the place of stones in ceremonial is apparently taken by wooden and Y-shaped posts, used by Semas, Sangtams, Kalyo-Kengyu, Chang and possibly other tribes, while the Ao uses round-topped posts or posts with a divided top. [30] The Garos, it may be noticed, also use the Y-shaped post, while the similarity of both the Y-shaped Sema post and the round-topped Ao post respectively to the bifurcated and round-topped stones left by the old Kachari kings at Dimapur is too close for mere coincidence. It should be added that Mr. Mills tells us that Lhotas occasionally substitute a Y-shaped post for a stone in their ceremonials where no stones suitable for erection can be found, while there is a kindred of a clan in Yekhum village which migrated from further east and which habitually erects posts, as it is not allowed to erect stones. [31] In building, again, while the Angamis, Tangkhuls, Semas and other tribes south of them build on the ground, the Aos and other tribes to the north build on a bamboo platform or “machan.” The Lhota method is a sort of compromise, as when he builds on a “machan” he covers the floor with earth.