RAVENHEAD COLLECTION IN THE BROWN FREE LIBRARY AND MUSEUM. 415 



carpus Noeggerathi is ever less than 2*5 cm., if so small ; whereas the longest specimen 

 of Trigonocarpus Parhinsoni that I have met with is 27 cm. long, but it was somewhat 

 compressed. Of course, the diameter of Trigonocarpus Parhinsoni is proportionally 

 smaller. 



Trigonocarpi have three prominent and three very slightly raised ridges placed 

 between the stronger ones, but it is only on well-preserved examples that the slightly 

 raised ridges or keels are observable. 



Of the two figures I have given of Trigonocarpus Noeggerathi, that in the Trans. 

 Roy. Soc. Edin., vol. xxxiii. part ii. pi. xxiii. fig. 3, represents the form named dubius 

 by Sternberg, which is, however, not specifically distinct from his Trigonocarpus 

 Noeggerathi. 



Trigonocarpus Parkinsoni, Brongt. 



Trigonocarpus Parkinsoni, Brongt., Prodrome, p. 137. 

 Trigonocarpus Parhinsoni, Kidston, Catal. of Palceoz. Plants, p. 217. 



Pinnularia, Lindley & Hutton. 

 Pinnularia capillacea, L. & H 



Pinnularia capillacea, L. & H., Fossil Elora, vol. ii. pi. cxi. 

 Pinnularia capillacea, Kidston, Catal. of Palmoz. Plants, p. 58. 



Stem. 



"Stem of a Fern," Marrat, Proc. Liverpool Geol. Soc, Session 13, 1871-72, pi. xi. fig. 1, 1872. 



Remarks. — A figure of one of these fossils has been given by Mr Marrat, who 

 regarded them as fern stems. They possibly may belong to that group of fossils, but 

 their state of preservation does not admit of a satisfactory determination. The stems 

 bear spirally arranged obovate scars, which are considerably elevated in their upper part, 

 but slope downwards towards their base, where they merge gradually into the stem, 

 which is longitudinally striated. 



[Index, 

 vol. xxxv. part ii. (no. 10). 3 z 



