476 Mi*. R. Kidston on some Fossil Plants 



Division B. Furrows on the stern not alternating at the 

 nodes or joints. 



Group IV. Arch^ocalamites, Stur (Aster ocalamites, 

 Schimper; Catamites, Brongniart). 



Branch-scars irregularly distributed. Joints unequal in 

 length. 



For the purpose of classifying these fossils, the groups 

 proposed by Weiss will be found most useful ; but perhaps 

 Nos. I., II., and III. had better be regarded at present as 

 convenient sections rather than genera. Group IV., on the 

 other hand, is so well defined, both as concerns its steins and 

 fruit *, that it must be regarded as a true genus and quite 

 distinct from Calamites. 



In geological distribution groups I.— III. are characteristic 

 of the Coal-measures ; group IV. of the Lower Carboniferous 

 ( = Carboniferous Limestone series and Calciferous Sandstone 

 series) . 



A good deal of discussion has taken place as to whether 

 the exterior surface of the bark of Calamites was smooth or 

 furrowed. It appears, as is often the case in such differences 

 of opinion, that both views are correct in part. It now seems 

 clearly proved that the species with thin bark show on their 

 outer surface the characteristic furrows, but, on the other 

 hand, the stems with thick bark show no trace of the fur- 

 rows on their outer surface. The decorticated stems, how- 

 ever, are always distinctly furrowed, and it is in this condition 

 that Calamites most frequently occur. This vexed question, 

 from the careful investigations of Prof. Weiss, seems to be 

 now satisfactorily settled. 



Group I. Calamjtina, Weiss. 



Calamites (Calamitina) varians, Sternberg. 



Catamites varians, Sternberg, Vers. ii. p. 50, pi. xii. 



Remarks. This specimen belongs to one of the forms of this 

 species, but is not in a good state of preservation. 

 Locality. Drumgray Coal, Airdrie. 



Calamites (Calamitina), sp. 

 Remarks. Unfortunately only a small fragment of this 



* The fruit of Areheeocalamites is the Pothocites Grantonii of Paterson. 

 See Ann. & Mng. Nat. Hist. May 1883, p. 297. 



