The term grotto was applied to a cave or cavern made by hollowing out the ground, as at the Woodlands, or digging into a bank or hillside, as at Lemon Hill and Monticello. While some grottos were formed out of a naturally occurring cavity or depression—as in the case of the grotto at Belfield—they could also be created artificially, complete with contiguous artificial rockwork [Fig. 1] or constructed simply as a stone summerhouse. They could also be made from a combination of natural and artificial elements. In 1771, for example, Thomas Jefferson described building up a natural cave with rock or clay, then covering it with moss or thatch.