584 



HISTORICAL GEOLOGY. 



of the genus Gaulopteris ; and C. advena Newb. is the name of another 

 species. The trunks of both are three to four inches in diameter. Newberry 

 states that these tree ferns probably grew over the region of the Cincinnati 

 uplift — then an island (C, map, page 412 or 536). 



Spores and spore-cases (sporangites) have been reported from the lime- 

 stone of Ontario County, N.Y. As described by J. M. Clarke they are y^ 

 and -^of an inch in diameter ; he suggests that they may be from Rhizocarps 

 (the lowest of Acrogens) of the genus Salvinia (p. 436), and they are referred 

 to the species Protosalvinia Huronensis of Dawson. 



Animals. — The Upper Helderberg period was eminently, as has been 

 stated, a coral-reef period, but besides corals, it abounded also in species of 

 other tribes of invertebrate life characteristic of Paleozoic time. 



1. Sponges. — The existence of Sponges is indicated by the presence of 

 their siliceous spicules in the hornstone, two slender forms of which are 

 shown in Figs. 853 j, h, and others in I, m, n. Besides, there are species of 

 AstrcBospongia and Hindia. There are also several species of Stromatopora^ 

 and the last known in America of ReceptacuUtes. 



Polyps.— Fig. 858, Zaphrentis gigantea; 859, Z. Rafinesquii; 860, PhUUpsastrea Verneuili ; 861, 861 a, Cyatho- 

 phyllum rugosum ; 862, Favosites Goldfussi ; 863, Syringopora Maolurii ; 864, Eomingeria cornuta. Figs. 

 858, 860, 862, Edwards and Haime ; 859, 861, Meek ; 863, Tandell and Shumard ; 864, Billings. 



2. Polyp-corals. — Figs. 858 to 864 represent a few of the many Corals: 

 859 shows the radiated cup-shaped termination to which the name Cyatho- 

 phylloid (from Kva6o<; cup, and (f>vX\ov, leaf) refers; 858 has both extremities 

 broken off, but exhibits the interior radiation. Fig. 862 represents a portion. 



