320 CARHONIFKROUS FORMATIONS AND FAHNAR OF COI.ORADO. 



took f() l)(' I'rodiictiix spiiu's, Iml. wliicli, it seems, can be properly fel'erred only to a 

 tsponj^c of the ifeims Ihiahiniclla. These bodies consist of nearly straight, smooth, 

 sl(\nder, cylindrical rods of several sizes, all, or nearly all, l.ying- in the, same dircc 

 tion, contig-nous and superimposed. Some of the largest have a diameter of but 

 little less than 0.5 nim., and one of them has been traced to a length of 82 mm. In 

 this distance the taper is almost imperceptible. Besides the large rods there are 

 others of almost hair-lik(> proportions, and altogether of both sorts there must be 

 many hundred. No anchoring hooks or other peculiar terminal formations have 

 been observed. While most of the spicules have a nearl}'^ or exactly identical direc- 

 tion, a few tine and fragmentary ones are directed more or less transversely to them. 

 There can lie little doubt that these bodies are the basal tuft of a sponge of a type for 

 which the name llyahmtdia was proposed. No spicules of different type have been 

 observed, the shorter ones being cylindrical like the larger and doubtless but frag- 

 ments of them. 



Locality and horizmi. — San Juan region, Silverton quadrangle (station 2279); 

 lower portion of the Hermosa formation. 



HYSTKIOSPONGIA Ulrich, 1890. 



HySTRIOSPONGIA ? Sp. 



From the same station which furnished the specimen of Hyalostelia just men- 

 tioned another quite different sponge was obtained. It occurs in a calcareous black 

 shale, on the surface of which it appears as a superficial entanglement of spicules, 

 with a circular shape and a diameter of about 20 mm. The spicules are so meshed 

 together that it is impossible to make out their characters as completely as desirable. 

 They seem to consist of fine, slender, rod-like elements, having a radial direction. 

 No trifid spicules have been observed, but such might readily escape notice. 



Locality and horizon. — San Juan region, Silverton quadrangle (station 2279); 

 lower portion of the Hermosa formation. 



CCEIjENTERATA. 



LOPHOFHYLLUM Milne-Edwards and Haime, 1850. 

 LoPHOPHYLLUM PROFUNDUM Milne-Edwards and Haime. 



1851. Cyathaxonia profunda. Milne-Edwards and Haime, Monog. des Polyp. Foss., p. 323. 



Carboniferous: Flint Eidge, Ohio. 

 1860. Cyathaxonia profunda. Milne-Edwards, Hist. Nat. Corr., vol. 3, p. 331. 



Carboniferous: Ohio. 

 1860. Ci/atliaxonia prolifera. McChesney, Desc. New Spec. Pal. F'oss., p. 75. 



Coal Measures: Widely distributed in the Western States. 

 1865. Cyalliaxonia prolifera. Mf:Chesney, Illustrations New Spec. Foss., pi. 2, figs. 1-3. 



