THE CLIMATE OF ACADIA IN THE EAELIEST TIMES. 7 



ceous appendages, which are kept in constant motion. In 

 the rapid flapping of these little fins, they resemble butter- 

 flies on the wing. These small creatures are protected by a 

 thin, translucent shell, usually of a conical form, but some- 

 times spiral, or sack-like. 



All these are animals which live and reproduce their kind 

 in the open ocean ; but there is another class of animals, 

 many of which are found in the deeper waters and which also 

 reproduce at a distance from the land, but in their adult 

 state are of much greater size and live upon the bottom of 

 the sea ; these are the sponges, an order of which the Eup- 

 lectella, or glass-sponge, may be taken as an example. This 

 animal is found in the China Sea and other closed seas of the 

 Pacific Ocean. 



Thus we see in contrast two groups of animals — those 

 that inhabit the warm shallow seas and those that may be 

 found in the deeper and colder parts of the ocean. The 

 forcing of marine animals into special associations shows thus 

 the existence of water of different temperature in the ocean, 

 just as we have the more familiar climatic differences that 

 modify the association and distribution of animals over the 

 surface of the land. 



As there are now tracts in the ocean occupied by waters 

 of different temperatures, so there were in the earliest 

 Palaeozoic times, and this is shown by the remains of marine 

 animals entombed in the rocks. In certain regions are found 

 the remains of the coral building forms and the molluscs, 

 which correspond to those of the warm, shallow seas of the 

 present day ; in other regions, as in the confines of this city, 

 and at various points in the Maritime Provinces, are entombed 

 the remains of animals corresponding to the Sertularians, the 

 Pteropods, the Glass-sponge and other forms of the open 

 ocean. 



