p. 7

development in every individual.

The plates of the summit partake of the same variable character in their surface markings, as those of the body below.

L. 1.4- D. 1.4

Middle Silurian-Niagara group

Lockport, Rochester, & Wolcott, N.Y. Root River, Wisconsin; (I.A.L.) Louisville Ky.
Decatur Co., Tenn.
(Bridgeport Ill)

Wauwatosa?
Racine