GEOLOGICAL HISTORY 47 
most note, however, is the advent on the scene of 
the first freshwater Mussel, Archanodon Jukesii, which 
is closely allied to, and greatly resembles, the modern 
Anodonta (Swan Mussel) of our ponds and lakes. 
A true Scaphopod (Dentalium) and representatives 
of the more primitive Ammonoidea (Clymenia) and 
the Goniatites likewise came into existence in the 
Devonian epoch. 
Just at the close of the Devonian epoch the first 
evidences are met with of the existence of Land 
Snails (Strophites, Dendropupa, etc.) allied to the 
Chrysalis Shells (Pupillidz); these were found in 
the plant beds at St. John, New Brunswick. The 
Coal-Measures of the succeeding carboniferous period 
have yielded some other interesting air-breathing 
Snails, including the oldest known terrestrial Rhipi- 
doglossate (Dawsonella); the first brackish-water 
Snail (Ampullaria); the earliest freshwater Snail, 
(Physa), both these last belonging to genera well 
known at the present day, besides the oldest known 
species (Zaptychius) of the most primitive of Pulmon- 
ates, the Auriculide, as well as other species of 
Dendropupa and a small Land Shell,* closely allied 
to the genus Pyvamidula, which is a common form 
to-day. Further examples of freshwater Bivalves 
belonging to the family Cardiniidz were plentiful 
in the Carboniferous, from which, too, the oldest 
exampie of a Tectibranch (Cylindrobullina) has been 
* Still miscalled Zonites in textbooks. 
