PALEOZOIC ROCKS AND ERA. 



309 



known with certainty. The general appearance is given 

 in Fig. 238. 



3. Calamites. These are so named from their jointed, 

 reed-like appearance (cala- 

 mus, a reed). They are usu- 

 ally found in the form of flat- 

 tened, jointed, and striated 

 stems. They may be de- 

 scribed as follows : Imagine 

 a straight, hollow, jointed, 

 tapering stem, one to two feet 

 in diameter, and twenty, 

 thirty, or forty feet high, ter- 

 minating in a compact, cone- 

 like fruit (Fig. 240), the joints 

 striated, but the grooves in- 

 terrupted at the joints by 

 whorls of scale-like leaves, or 

 else whorls of jointed, thread- 

 like branches (Fig. 239) about 

 the joints. From the basal 

 joints come out thread-like 

 roots. Fig. 239 is a restora- 

 tion of its appearance. 



Now, all that we have said applies, word for word, to 

 equisetse, or horse-tails, except the great size. But equi- 

 setse of the present day are small, rushlike or reedlike 

 plants. Moreover, the internal structure of Calamites 

 shows a close relation with gymnosperms, probably coni- 

 fers. 



Conclusion. The general conclusion, then, is that all 

 the plants of the Coal, but especially the Lepidodendrids, 

 the Sigillarids, and the Calamites, were remarkable gen- 

 eralized types, connecting classes and orders now widely 

 separated from each other viz., the higher or vascular 

 cryptogams with the lowest or gymnospermous pheno- 



FIG. 239. Restoration FIG. 240. Fruit 

 of a Calamite. (Af- of Calamite. 

 ter Dawson.) (After Heer.) 



