Robert BrownOur eath and its story: A Popular Treatise on Physical Geography, vol. 2, Londres, Cassell & Co., 1890, p. 30.

The coprolites, which, as we know, are the droppings of extinct animals, are also in they way fossils, just as the cases of extinct caddis-worms are as much proofs positives of the existence of the neuropterous.