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STRATIGEAPHICAL GEOLOGY 



coal-seams, while their roots (Stigmarice) ramify in the under-clays 

 beneath. They were tall trees, branching at the top, and rivalling 

 the Lepidodendra in height, with a bare trunk fluted longitudinally, 

 and regularly ornamented by the pits or scars left at the points 

 where the leaf-stalks were attached. These leaves were long and 

 narrow, and similar to those of Lepidodendron. The fruit consists 

 of small sporangia borne at the basis of slightly modified leaves ; 

 Sigillaria was therefore a Lycopod, and allied to Lepidodendron. 



Fig. 06. GROUP OF COAL-MEASURE PLANTS. 



a. Calamites cannseformis (root end). c. Sigillaria reuiformis. 



6. Alethopteris lonchitica. d. Lepidodendron Sternbcrgi. 



c. Stigmaria flcoides. 



Stigmaria}. The roots of Sigillaria, Lepidodendron, and Bothro- 

 dendron are so much alike that it is impossible to distinguish 

 them. Consequently they are all known as Stigmaria, long, branch- 

 ing, and tapering, with numerous rootlets spreading out in all 

 directions ; such roots have been found which were upwards of 

 20 feet in length. Perhaps, like those of the modern mangrove - 

 tree, these roots were partly aerial, rising well above the low-water 



