IX] EQUISETITES COLUMN ARIS. 269 



nodes are marked by comparatively deep constrictions, which 

 probably represent the projecting nodal wood. The surface of 

 the casts is traversed by regular ridges and grooves as in an 

 ordinary Calamite, and it is probable that in Equisetites 

 arenaceus, as in Calamites, these surface-features are the im- 

 pression of the inner face of a cylinder of secondary wood 

 {cf. p. 310). Excellent figures of this species of Equisetites are 

 given by Schimper in his Atlas of fossil plants \ also by Schimper 

 and Koechlin-Schlumberger^, and by Schoenlein and Schenk*. 



5. Equisetites columnaris Brongn. Figs. 11 and 58, B. 



This species, which is by far the best known British 

 Equisetites, was founded by Brongniart'' on some specimens 

 from the Lower Oolite beds of the Yorkshire coast. Casts of 

 stems are familiar to those who have collected fossils on the 

 coast between Whitby and Scarborough ; they are often found 

 in an erect position in the sandstone, and are usually described 

 as occurring in the actual place of growth. As previously 

 pointed out (p. 72), such stems have generally been de- 

 posited by water, and have assumed a vertical position 

 (fig. 11). Young and Bird^ figured a specimen of this species 

 in 1822, and in view of its striking resemblance to the sugar- 

 cane, they regarded the fossil as being of the same family as 

 Saccharum officinarum, if not specifically identical. 



A specimen was described by Konig'' in 1829, from the 

 Lower Oolite rocks of Brora in the north of Scotland under the 

 name of Oncylogonatum carbonarium, but Brongniart' pointed 

 out its identity with the English species Equisetites columnaris. 



Our acquaintance with this species is practically limited to 

 the casts of stems. A typical stem of E. columnaris measures 

 3 to 6 cm. in diameter and has fairly long internodes. The 



1 Schimper (74) Pis. ix— xi. 

 3 Schimper and Koeohlin-Sohlumberger (62). 

 3 Schoenlein and Schenk (65) Pis. i— iv. 

 * Brongniart (28) p. 115, PI. xiii. 



5 Young and Bird (22) p. 185, PI. iii. fig. 3. 



6 Konig, in Murchison (29) p. 293, PI. xxxii. 



7 Murchison (29) p. 368. 



