The ancient Indian text Brihat Samhita, compiled by Sage Varahamihir in 412 AD, describes indicators that can be used to predict the presence of underground water sources. These natural signs include specific trees, plants, herbs, grasses, hibernating animals, and anthills. The 54th chapter contains 124 verses detailing various plants and their association with water at certain depths and distances, such as the presence of a Rotang tree indicating water 7.5 cubits deep, 3 cubits west of the tree. A number of trees and plants that can serve as indicators are illustrated.