48 MR ROBERT KIDSTON ON 



As already mentioned, it is very rarely that one finds specimens of Sigillarise with 

 the leaves still attached. I only possess two with the foliage connecting with the 

 stem. One, the Sigillaria (Ulodendron) discophora, Konig, sp., where the leaves are 

 lanceolate, single nerved, about 1^ inch long and ^ inch wide ; the other, Sigillaria 

 eamptotoenia, Wood, sp., where the foliage is of the long grass-like type, about -§• inch wide ; 

 but they are so broken on my example that their full length cannot be determined, but 

 they must have been of considerable length. From the descriptions and figures of 

 several writers, this appears to have been the prevailing type of leaf among the Sigillarise, 

 and is, in fact, the Cyperites bicarinata, L. and H.,* though the description by these 

 authors seems to be erroneous, in so far as they ascribe to the leaf two sub-lateral 

 veins. 



Though Sigillaria occurs in the Permian Formation, it is essentially a Carboniferous 

 genus, and even here it is rare, except in the Upper Carboniferous. From the Lower 

 Carboniferous of Britain 1 only know of two species, — the Sigillaria (Ulodendron) 

 Taylor i, Can, and the Sigillaria Youngiana, Kidston.f The former belongs to the 

 Clathrarian section, and occurs in both the divisions of the Lower Carboniferous ; and 

 the latter, belonging to the Rhytidolepis section, is only known by a single specimen, 

 which was discovered in the Carboniferous Limestone Series of Scotland by Dr John 

 Young of the Hunterian Museum, Glasgow, and is the only example of a ribbed Sigillaria 

 1 have seen from Lower Carboniferous rocks. In the Middle Coal Measures the 

 Sigillarise, especially the ribbed forms, appear to attain their maximum period of 

 development in Britain. 



A prevalent idea seems to have taken possession of many geologists that every trunk 

 found in Carboniferous rocks belongs to Sigillaria, and several trunks occurring in the 

 Lower Carboniferous have been publicly announced as such ; but in no case have any of 

 these stems, so far as I have been able to trace, ever shown any characters, either on 

 their outer surface or impressed upon the surrounding matrix, in support of this popular 

 but erroneous belief. On the other hand I have in two cases been able to prove 

 conclusively that certain large stems which occurred in the Calciferous Sandstone Series 

 belonged to Lepidodendron Veltheimianum, Sternb. I possess a specimen which was 

 sent to me as one of these so-called Sigillaria, but in receiving portion of the enveloping 

 rock the leaf-scars of Lepidodendron Veltheimianum were clearly impressed upon it. lj: 

 Between this impression and the ribbed core a layer of coaly matter was inserted. In 

 certain liepidodendra the bark of old stems splits into longitudinal clefts by the increase 

 of the stem in girth, and it is the casts of such fossils which give rise to these so-called 

 Sigillaria. Sir William Dawson called attention to these old irregularly ribbed stems 

 of Lepidodendron in his " Report on the Fossil Land Plants of the Lower Car- 

 boniferous and Millstone Grit Formations of Canada," in 1873, when he pointed out 



* Fossil Flora, vol. i. pi. xliii. figs. 1-2. 



t J'roc. Hoy. I'hys. Soc, vol. xii. p. 261, pi. vi. ligs. 2, 2«, 1894. 



X From the left bank of tlie Water of Leith, a little above Spylaw House, Colinton, Midlothian, Reg. Nos. 67 

 and 68. 



