PENNSYLVANIAN FOSSILS 



107 



Lepidodendron , often squashed flat, are common in parts of our Pennsylvanian. 



Lepidocarpon (fig. 281) has cones composed of seed-like structures, is proba- 

 bly related to Lepidodendron or allied genera, and is found in the same rocks. 



282) is similar to Lepidodendron but the leaf -scars are in 

 Cones, 



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Fig. 282 



Sigillaria (fig 

 Fig.28i longitudinal rows. 



generally regarded as 

 related to Sigillaria , are identified 

 as Sigillariostrobus . Some of the 

 trunks of Sigillaria were large trees 

 about 100 feet high. It is a common 

 genus in the Pennsylvanian of Ohio. 



Stigmaria (fig. 283) is the name 

 applied to the roots of scale trees. 

 The surface has circular scars in 

 regular spirals; they mark the point 

 of attachment of rootlets. Stigmaria 

 is a very common type of fossil in 

 the clays under some of our Penn- 

 sylvanian beds. 



Cordaites (fig. 284) is dis- 

 tantly related to modern conifers. 

 It belongs in the phylum Conifer - 

 ophyta. The Cordaites were large 

 trees 100 feet or more high, with a 

 diameter of about 2 feet. The 



surface bore numerous spirals of Fig. 28 



sessile leaves up to 2 and 3 feet long, 



sword-like in shape. Cordaites is well represented by large leaves in the Pennsylvanian 

 Ohio. 



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PROTOZOA . The most conspicuous protozoans 

 of the Pennsylvanian are the fusulinid Foraminifera. 

 They are small, l/4 inch or less long, and shaped 

 Fig. 284 like a wheat grain (fig. 285). They occur in our 



marine limestones, sometimes in great abundance. 

 Specimens must be sectioned for even generic identification, so it seems pointless 

 to differentiate them here. Several genera and species have been recorded from 

 Fig. 285 Ohio. See Thompson (1936) and Smyth (1951). 



ANTHOZOA. Corals are scarce in our Pennsylvanian rocks. The 

 only form which is common enough to be noted here is a small cup coral, 

 Lophophyllidium profundum (fig. 286), abundant in places. 



BRYOZOA . Leafy and twig-like bryozoans are common in some of 

 the limestones and shales of our Pennsylvanian. In addition, a curious 

 parasitic form, Bascomell a, has been described from Ohio. It bored into 

 the shell of brachiopods and pelecypods. The commoner genera may be 

 identified by means of the following key. The species are figured by Meek 

 (1875), Foerste (1887, pp. 71-88), Mark (1912), and Morningstar (1922). 



Fig. 286 



