SUPPLEMENT. 13 



variety of T.formosa, as I think that some forms tending to connect them may be found 

 in the specimens obtained by Mr. Witchell, which would reduce the distinction to indi- 

 vidual peculiarities ; they are, however, fully worthy of being figured and compared. I 

 would also more especially direct the attention of foreign palroeontologists to the figures of 

 T.formosa, when no reliable British specimens can be obtained, as I have repeatedly 

 been requested to show them the two species placed side by side for comparison. I am, 

 however, quite satisfied with the figures of T. striata (Plate V, figs. 6', 7, and 8), and 

 would request them to compare the siphonal and hinge-borders of these three figures with 

 the corresponding parts of T. formosa. I fear that fig. 6 {T. formosa) of Plate V has 

 sometimes been mistaken for T. striata in mistake for C of the same plate, which in its 

 explanation is misprinted 3. 



The figured specimens are from the Inferior Oolite near Stroud. 



TriiooNiA GKMMATA, Li/cett. Trigou. Monogr., Plate I, fig. 7 ; Trigon. Supplement, 



Plate II, fig. 6 ; var. bifcra, Plate II, fig. 7. 



The unusually well-preserved specimen of this rare little species herewith figured has 

 been forwarded to me by Mr. Walford from the Hook Norton locality, where apparently 

 it occupies a lower position in the Inferior Oolite (beds B and C) than in the Cottes- 

 wolds. The surface ornaments are minutely and delicately preserved. 



Figure 7 on the same plate represents a specimen of the variety bifera, obtained by 

 Mr. Witchell from the Inferior Oolite of Rodborough Hill, and described in a footnote, 

 page 239. Mr. Witchell has also kindly forwarded to me other specimens of T. gemmata 

 from the Clypeus-grit of the Stroud district ; these, unfortunately, all imperfect, are 

 chiefly remarkable for the minuteness of their ornamentation. 



I have also discovered a specimen from the Dogger at Blue Wyke, North York- 

 shire. In common with the fossils generally that crowd those beds in that locality, 

 it is wanting in the delicacy of preservation which is often found in the fossils of Oxford- 

 shire and of the Cotteswolds, and notably so in the Oxfordshire specimen here figured. I 

 mention its occurrence on account of the geological position, which aj)pears nearly to agree 

 with that of the Oxfordshire form, and near the base of the Inferior Oolite ; the 

 Cotteswold examples, on the other hand, come from the highest beds of the formation. 



Trigonia producta, Lycett. Trigon. Monogr., Plate XIII, figs. 1, 2, 3, 4 ; and Plate 



XXXVII, figs. 1, 2; Trigon. Supplement, Plate II, 

 figs. 4, 5. 



The smallest of our figures (Suppl,, Plate II, fig. 5), from the Clypeus-grit of the 



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