No other shell

William Jardine, Memoirs of Hugh Edwin Strickland, Londres, John Van Voorst, 1858, p. XXXIII.

The limestone is entirely composed of indusiae of Phryganea, coated with shells of a species of Paludina. No other shell was noticed excepted a Helix. The beds of this limestone were from 3 to 6 fect apart, and interstratifield with the marl.