142 DR ROBERT KIDSTON ON THE 



badly preserved, and possibly do not belong to this species. They are therefore 

 excluded from the references.* From typical Sigillaria mamillaris Brongt., Sigillaria 

 trigona is essentially distinct, the former belonging to the Rhytidol&pis section (those 

 with straight or only slightly flexuous furrows), while the latter belongs to the 

 Favularia section, but in Sigillaria Dournaisii Brongt., + which is now united to 

 Sigillaria mamillaris as a variety of that species, when the scars are large and occupy 

 almost the whole width of the ribs, which then become slightly enlarged and somewhat 

 zigzag, some similarity between the two species occurs, but the " bell-shaped" scars of 

 Siyillaria trigona and the pronounced zigzag furrows will at once distinguish them, 

 and further, the rib below the leaf scar is always distinctly ornamented with transverse 

 bars in Sigillaria mamillaris and its varieties. 



Still more closely related to Sigillaria trigona is the Sigillaria Hauchecornei 

 Weiss.J Here, however, the leaf scars are slighly broader in proportion to their length 

 and the two ridges below the leaf scars extend downward from the margin of the scar 

 itself, while in Sigillaria trigona they are only on the cushion proper below the 

 leaf scar.§ 



The Sigillaria trigona Sternb., sp., is very rare in Britain. 



Horizon and Locality. — Roof of Thick Coal : Tipton. 



Sigillaria tessellata Brongt. 



1818. Phgtolithus tessellatus, Steinhauer, Trans. Amer. Phil. Soc, vol. i. p. 295, pi. vii. fig. 2. 

 1836. Sigillaria tessellata, Brongt., Hist. d. veget.foss., p. 436 ("? pi. clvi. fig. 1), pi. clxii. figs. 1-4. 

 1886. „ „ Zeiller, Flore foss. bassin houil. d. Valen., p. 561, pi. Ixxxv. figs. 1-9, 



pl. lxxxvi. figs. 1-6. 

 1911. ,, ,, Kidston, Mem. Musee roy. d'hist. nat. de Belgique, vol. iv. p. 188. 



1836. Sigillaria Knorrii, Brongt., ibid., p. 444, pl. clvi. figs. 2-3 (? pl. clxii. fig. 6). 

 1836. Sigillaria alveolaris, Brongt. (non Sternb.), ibid., p. 443, pl. clxii. fig. 5. 

 1848. Sigillaria contigua, Sanveur, Veget.foss. d. terr. houil. Belgique, pl. lii. fig. 1. 



Note. — Frequent. 

 Horizons and Localities. — 



Blue Measures, six feet above Brooch Coal : Hamstead Colliery, Great Barr. 

 near Birmingham. 



Ten-foot Ironstone Measures : Cabbage Hall Pits, Netherton, near Dudley. 



Blue Measures : Doulton's Clay Pit, Netherton, near Dudley. 



Roof of New Mine Coal: Mount Pleasant, Brierley Hill. 



Roof of Fireclay Coal: Doulton's Clay Pit, Netherton. 



Roof of Bottom Coal: No. 120 Pit, Coneygre Colliery, Tipton. 



* Vers. d. bohm. Ahlager., Abth. iii. pl. ix. figs. 3-5, 1876. 



t Sigillaria Dournaisii Brongt., Hist. d. veget.foss., p. 441, pl. cliii. fig. 5. 



X Sigillaria d. preuss. Steink, No. I. p. 47, pl. xiii. figs. 81-82, 1887. 



§ Koehnk uniie.s Sigillaria Hauchecornei Weiss with Sigillaria mamillaris as a variety. 



