It was publicly stated not long since that of all the Silurian strata there were no two so closely connected as the Liandilo and Caradoc groups. At the time this seemed a bold assertion, considering the great number of genera which were then thought to originate in the latter, not being known in the former. Some new forms, however, that have lately come to light from the Llandilo flags, shoe the connection between the two strata to be closer than it formerly appeared.