X] HISTORICAL SKETCH. 297 



casts are those of reeds or grasses. He goes on to saj' that the 

 material filling up the hollow pith of a reed would not have 

 impressed upon it a number of ribs and grooves such as occur 

 on the Calamites. He considers it more probable that the 

 casts are those of some well-developed tree, probably a foreign 

 plant. Equisetu7n gic/anteum L. is mentioned as a species with 

 which Calamites may be compared, although the stem of the 

 Palaeozoic genus was much larger than that of the recent 

 Horse-tail. The tree of which the Calamites are the casts 

 must, he adds, have possessed a ribbed stem, and the bark must 

 also have been marked by vertical ribs and grooves on its inner 

 face. It is clear, therefore, that Suckow inclined to the view 

 that Calamites should be regarded as an internal cast of a 

 woody plant. Such an interpretation of the fossils was 

 generally accepted by palaeobotanists only a comparatively few 

 years ago, and the first suggestion of this view is usually 

 attributed to Germar, Dawes, and other authors who wrote 

 more than fifty years later than Suckow. 



One of the earliest notices of Calamites in the present 

 century is by Steinhauer', who published a memoir in the 

 Transactions of the American Philosophical Society in 1818 on 

 Fossil reliquia of unknown vegetables in the Carboniferous rocks. 

 He gives some good figures of Calamitean casts under the 

 generic name of Phytolithus, one of those general terms often 

 used by the older writers on fossils. Among English authors, 

 Martin^ may be mentioned as figuring casts of Calamites, which 

 he describes as probably grass stems. By far the best of the 

 earlier figures are those by Artis' in his Antediluvian Phytology. 

 This writer does not discuss the botanical nature of the 

 specimens beyond a brief reference to the views of earlier 

 authors. Adolphe Brongniart*, writing in 1822, expresses the 

 opinion that the Calamites are related to the genus Equisetum, 

 and refers to M. de Candolle as having first suggested this 

 view. In a later work Brongniart^ includes species of Cala- 

 mites as figured by Suckow, Schlotheim, Sternberg and Artis in 



1 Steinhauer (18), Pis. v. and vi. ^ Martin (09), Pis. viii. xxv. and xxvi. 

 3 Artis (25). * Brongniart (22), p. 218. 



5 Brongniart (28), p. 34. 



