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 (Pupillidae) ; 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 (Ampidlaria) ; 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 Auriculidae, as well as other species of 

 Dendropupa and a small Land Shell,* closely allied 

 to the genus Pyramidula, which is a common form 

 to-day. Further examples of freshwater Bivalves 

 belonging to the family Cardiniidse were plentiful 

 in the Carboniferous, from which, too, the oldest 

 example of a Tectibranch (Cylindrobullina) has been 

 * Still miscalled Zonites in textbooks. 



