PLATE XI. 



Fig. 



1. Trigonia Pellati, Mun. Chal. Kimmeridge Clay, near St. Ives. (Page 41.) 



2. ,, formosa. Lye. Inferior Oolite, Rodborough Hill, near Stroud ; specimen 



with the costse deformed. (Page 35.) 



3. „ perlata, Ag. Coral Rag, Pickering ; specimen with the pallial portions of 



the costae irregular. (Page 22.) 



4. 5. „ clytia, D'Orb. Great Oolite, Box near Bath. (Page 76.) 



6, 7. „ „ Impressions of small Trigoniae, probably young examples of T. 



v.-cosfata. Colly weston Slate. (Page 66.) 



8. „ paucicosta. Lye. Kelloway Rock, Cayton Bay, near Scarborough. 



(Page 57.) 



9. „ „ Young example of the same species, from the same locality and 



fonnation. 



