783 



Proto. 



and solitary sponge spicules, large and small, some extremely 

 slender, others large, long, stout and straight, some parallel, 

 others divergent, or radiating, some anchoring, others perhaps 

 defensive. Dawson, page 52, 53. — See Spong^es. 



Protostigma. 



Sigillarioides, 



Lesquereux, Proceedings 

 of the American Philoso- 

 phical Society, Philadel- 

 phia, 1877. Collet's Indi- 

 ana Geological Report for 

 1883, plate 3, fig. 7,7 a; 

 from the Cincinnati ( Hud- 

 son river) slate formation- 

 Ill h 



1883 PK 3, 



Prototaxites logani, Dawson. {Nematophycus logani^ 

 Oarruthers.) Q. J. G. S. London, Vol. 15, page 484. Supposed 

 by Dawson to be the oldest known exogenous tree in America. 

 Supposed by Oarruthers to be a large sea weed. Devonian, 

 Yllh IX, 



Prototypus hitehcocki. {Angelina hitchcocki, Whitfield, 



L .^ ....^ P Jf pi ^4^ f^ ;i3 >) Walcott, Bulle- 



tin No. 30, U. S. G. S. page 211. 

 plate 31, fig. 4, type specimen 

 figured by Whitfield. lower 

 Cambrian {Georgian) forma- 

 tion Parker's quarry, Vermont, 

 Z. C\ 



