For instance, until recently not a land-shell was known belonging to either of these vast periods, with the exception of one species discovered by Sir C. Lyell and Dr. Dawson in the carboniferous strata of North America;
Esate baterako, oraintsu arte ez zen ezagutzen aldi luze horietako lehorreko maskorrik, Sir C. Lyell eta Dawson doktoreak Ipar Amerikako ikatzaroko estratuetan aurkituriko espezie bat salbu;