CHEMUNG PERIOD. 



289 



II. Life. 



The Chemung period was as profuse in life as any that preceded 

 it, and yet was almost wholly different in its species from the 

 Hamilton. 



1. Plants. 

 Besides the Cauda- Galli Sea-weed, there are remains of many land- 

 plants ; and thus we find that after the first appearance of an un- 

 equivocal land-plant their relics are no longer rare fossils. 



Figs. 502-504. 



Fig. 502, Sphenopteris laxus; 503, Lepidodendron Vanuxemi; 504, Atrypa Hystryx. 



In the Portage there are great numbers of Fucoids, or forms 

 regarded as fucoidal. The most common kind appear like short, 

 straight, simple stems, two or three inches long, scattered thickly 

 over the surface of the flagstones. In the Upper Portage there are 

 other cylindrical forms penetrating vertically the layers ; but these 

 are probably the fillings of worm-holes, analogous to those of the 

 Potsdam sandstone (p. 185). 



2. Animals. 

 The Portage beds, though abounding less in fossils than the Che- 

 mung, contain various species of Crinoids, Brachiopods, Conchifers 

 (Aviculopectens, Aviculce, and others), Bellerophons, and Goniatites. A 

 large Crinoid — the Cyathocrinus f ornatissimus — occurs in great num- 

 bers, broken to fragments, through a small area in the town of 

 Portland, on Lake Erie. 



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