82 LOWER PENINSULA. 



SYRINGOPORA FIBRATA, N. Sp. 



Large convex colonies, with closely approximated subparallel 

 or diverging tubules half a millimeter in diameter, laterally con- 

 nected by numerous short transverse channels, branching off at 

 close intervals from the circumference of the thread-like stems. 

 The distance separating the stems is variable — sometimes less, some- 

 times more than one tube diameter. Radial crests long, very distinct, 

 twelve in number. Diaphragms direct transverse, not funnel-shaped. 

 This species very frequently grows up in intimate connection with 

 expansions of Stromatopora. The tissue of the Stromatopora fills 

 out all the interstices left between the tubules, which in such speci- 

 mens are usually further apart than in those growing solitary. Both 

 hold in their growth an equal passus, and the addition of new 

 layers to the Stromatopora coincides with the growth of the 

 tubules. It resembles Syringopora compacta, Billings, found in 

 the strata of Anticosti ; but in that species the tubules are in almost 

 perfect contiguity, and their diaphragms are distinctly funnel- 

 shaped. 



Common in the Niagara group of Point Detour, Drummond's 

 Island, and frequently found in the drift. It occurs also in the 

 Niagara group of Indiana, Kentucky, and Iowa. 



Plate XXX.- — Fig. 3 gives a surface view of a silicified specimen 

 from Drummond's Island. 



SYRINGOPORA PERELEGANS, Billings. 



Colonies of tubular stems, from one and a half to two millimeters 

 in diameter, formed at the base of prostrate tubes, multiplying by 

 bi- or tri-partite ramification, in the same manner as Aulopora, by 

 production of one or two young tubes sprouting from the basal por- 

 tion of their flanks, which creep on for some distance, while the 

 mother-tube bends its orifice into an erect position, after having 

 given off the branches. The spreading, prostrate, basal tubes, flat- 

 tened on the lower side, come in multiple contact with their sides 



