(19). A piece of a kind of jasper stone, almost like a heart, polished, being a piece of that famous obelisk that now standeth in the chiefest place of Rome, called Piazza Navona, olim Circus Agonalis, set up there on a most magnificent fabrick, like a rock, out of which floweth 4 fountains, very large, signifying by the figures of colossean statues of the 4 rivers of Europe, Asia, Africa, and America, by the hand of Cavalier Bernino, that famous architect, my neighbour and friendly acquaintance, -- Pope Innocent the 10th being at that vast expense.