By boundary is under-stood, in general, every separatlon, natural or artificial, whlch marks the confines or line of division of two contiguous estates. Trees or hedges may he planted, ditches may be dug, walls or inclosures may be erected, to serve as boundaries. But we most usually understand by boundaries stones or pieces of wood inserted in the earth on the confines of the two estates. Civ. Code La. art 826