FOSSILS OF THE 



PORIFERA. 

 Genus PAL^EOMANON Eoemer. 



Palasomanon Roemeri, n. sp. 

 Plate xiii, fig. 12. 



This is a crateiform or cup-shaped sponge of the general form of those 

 referred to the genus Manon of the Jurassic and Cretaceous, and for the 

 reception of the Paleozoic types of which Dr. Roemer founded the genus 

 Palseomanon, making P. cratera of the Niagara Group the type. 



The example of P. Eoemeri before me has a height of 65 mm , and a diam- 

 eter of. oO mm , contracting below to form a rounded base; the outer wall 

 extends vertically to within a short distance of the summit, where it curves 

 inward to the rounded marginal rim of the shallow cup; this has a depth of 

 15 mm . Owing to the complete silicification and change of the original 

 spiculae, none of the surface characters have been preserved; the unmis- 

 takable, striking form serves for the generic and specific identification. 



Formation and locality. Lower horizon of the Devonian limestone at 

 Lone Mountain, 18 miles northwest of Eureka, Nevada. 



Genus ASTYLOSPONGIA Eoemer. 

 Astylospongia, sp. ? 



Several specimens of a rather small, globose or flattened oviform sponge 

 were obtained from the center of cherty concretions. The largest has a 

 diameter of 30 mra , and presents in a transverse section numerous fine, radi- 

 ating tubes or canals studded with fine spiculse. Owing to the imperfect 

 preservation of all the specimens, it is impossible to determine their specific 

 relations to forms already described. 



Formation and locality. Lower horizon of the Devonian limestone at 

 Lone Mountain, 18 miles northwest of Eureka, Nevada. 



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