CLASS II 



STROMATOPOROIDEA 



123 



or at leas't a considerable number of laminae ; in vertical sections, accordingly, 

 exhibiting a quadrate meshwork. The laminae consist of an anastomosing 

 network of calcareous fibres, generally having a porous structure; their surfaces 

 are covered with projecting granules or tubercles, which represent the free 

 upper ends of the vertical pillars. Kare in the Silurian, but very abundant 



, ■ ■ ~~^^r^f^y^~^p^ 







Fig. 190. 



Strom(ttopora tubercvlata Nich. Devonian 

 (Corniferons limestone) ; Jarvis, Ontario, 

 Natural .size (after NicholsonV 



Fio. 101. 



Oniniopora %ilacenta Phill. Devonian; Torquay, 

 Devonshire. .4, Tangential .section, natural size. 

 K, The same, highly ma^'uified ; n, Vertical " Cauno- 

 pora tube " ; h, Canal partially cut into ; c, Calcare- 

 ous fibres traversed by delicate ramifying canaliculi. 

 C, Vortical section, highly magnified. 





in Devonian of the Eifel, England and North America. A. clathratum Nich, 

 (^ = Stromafopora concentrica p. p., Goldf.). 



Clathrodidijon Nich. Like the preceding, but wnth radial pillars extending 

 only between the upper and lower surfaces of successive laminae. Character- 

 istic of Silurian ; rare in Devonian. 



Stromatopora G;o\Ai. emend. Nich. (Pa%s^?-o??ifl Nich. and Murie) (Fig. 190). 

 Radial pillars uniting with the thick concentric strata or latilaminae to form a 

 finely reticulated tissue, in Avhich tabulate zooidal 

 tubes are sparsely distributed. Plentiful in Devon- 

 ian ; less common in Silurian. 



Caunopora Lonsdale (Fig. 191), and Diapora 

 Bargat., are Stromatoporoids which are indis- 

 tinguishable from other genera except by the 

 presence of numerous definitely walled tubes pene- 

 trating the coenosteum at closer or remoter in- 

 tervals. The tubes are often thick-walled, are 

 furnished with horizontal or funnel-shaped tabulae, Hcr?)!n!>)stro7Hosp.ind. Devonian; 



1 • n •,! L ^ • • „ Torquay, Devonshire, a, Hori- 



and occasionally with septal spines; in many cases zontai "lamina composed of two 

 they evidently represent the corallites of Anlopora f-terillin'I'XmL^fet-'rRLiiai 

 and Si/ringopora colonies, which have become en- piiiar traversed by axiai canai. 

 veloped, but have continued to live coramensally 



within the tissues of the Stromatoporoid. In other cases, however, the tubes 

 appear to have been formed by true Stromatoporoid polyps. Devonian. 



Hermato stroma Nich. (Fig. 192). Massive or foliaceous skeletons, composed 

 of thick parallel latilaminae, connected by vertical pillars ; pillars often running 

 continuously through several concentric laminae. Both pillars and laminae 

 exhibit a dark median line Avhen view^ed in cross-section, indicating either the 

 presence of axial canals or composition out of two lamellae. Devonian. 



Fio. 192. 



