The beginnings of picture-writing were in use among them, and the remarkable rock inscriptions still visible on the Orinoco and the Essequibo are attributable to them, and were probably intended as conjurations to the supernatural powers, similar to others which remain in St. Vincent and other islands from the date of the Carib occupation.[387] Their family life was not usually communal, but each household occupied its own dwelling. In some parts, as in the deltas of the Essequibo and Orinoco, and even on the dry savannas, their huts were built on a substructure of piles which lifted them five or six feet from the ground or the water, as the case might be. The religious rites they observed were often elaborate. Their principal divinities are said to have been the sun, moon and earth, the latter of which was spoken of as the mother of the race. They practiced the _couvade_, and their priests, called _piaye_, exercised unlimited power, and were correspondingly feared. It was the opinion of Von Martius that the Carib, the Tupi-Guarani and the Arawak stocks are traceable to some very ancient common tongue. This view is at first sight strengthened by a wide comparison of vocabularies, but is weakened by an examination of the grammars of the three families, especially their pronominal elements. It is probable that the three ancestral tribes had early and close communication, but not original identity. The seeming relationship has been rendered more prominent in certain instances by free later borrowings. M. Adam has shown that some of the northern dialects are in the condition of jargons, their grammar on the Carib model, their words drawn from various stocks. Such are the “Island Carib,” which is largely Arawak, and the Boni-Ouyana, described by Dr. Crévaux.[388] CARIB LINGUISTIC STOCK.