42 E. A. WALFOED ON THE STEATIGEAPHICAL 



The abundance of rolled nodules, covered often by fine colonies 

 of Serpujae, and also pierced by boring shells, point to a pause in 

 sedimentation prior to the deposition of the clays of the Fuller's 

 Earth. In the south-west of England T. producta is confined to 

 the Trigonia-grit. 



Trigonia approaching v-costata, Lye. — Both T. v-costata and 

 T. conjungens must be catalogued as doubtful species of the jSTorth 

 Oxfordshire area. The former is common in the lowest bed of the 

 Inferior Oolite at Moulton near J^orthampton, and is found also in 

 the Lincolnshire Limestone of the Midlands. In Yorkshire it occurs 

 in the Dogger, and in Gloucestershire in the Oolite Marl and Trigonia- 

 grit. T. sharpiana, Lye, with which this species is often associated 

 in the Dogger and Northampton Sand, I have failed to recognize in 

 Oxfordshire, though in the " Cynocephala stage " of Yeovil Junction, 

 I have collected what appear to be but slightly diverging forms. 



Teigonia AEDUEio-Ay E. & S. — The fragment from Hook Norton, 

 figured by Lycett in the last supplement, is, so far, the only record 

 of this early Bathonian species of Rigaux and Sauvage. 



Teigonia Ltcettii, nov. sp. (PI. I. figs. 1 & 2.) 



Shell ovately trigonal, convex, height of full-sized specimen IJ 

 inch, breadth Ig inch, width of area ^g- inch. Umbones slightly 

 recurved, antero-mesial, anterior border moderately produced and 

 curving gracefully with the lower border, hinge-line straight, length 

 rather more than half the height of the shell and sloping steeply 

 downwards ; costse about sixteen, solid and unbroken in the earlier 

 stages, cord-like on the lower two thirds of the valve ; the first 

 four or five pass with but slight downward curvature over the 

 surface, and form knots at the carina, passing also with slight Y- 

 shaped inflexion over the area and somewhat less prominently over 

 the escutcheon also. The other costse sweep downwards, curve with 

 the lower border, break and are replaced by a few tubercles in the 

 middle third of the valve, and then, becoming solid and very much 

 thickened, pass upwards at a high angle to the carina, across which 

 they (the costse) pass with bold undulation. The area has a slight 

 median inflexion or line only, and is crossed everywhere by the 

 thick costae which pass over it without interruption. There are, 

 however, indications of fine costellse at the posterior part of the 

 area. The ante-carinal depression is so pronounced in one specimen 

 as to form a double row of nodulations, one row upon the carina 

 and another row upon the anterior side of the furrow resembling 

 the nodulations of T. ar duenna, E. & S.*, as figured by Messrs. 

 Eigaux and Sauvage in their excellent memoir. The escutcheon 

 is shallow and lengthened. 



Figure 1 shows the normal and typical form. The other example 

 (fig. 2) is almost distinct enough for a varietal name. In it the 



^ " Descr. de quelques especes nouvelles de I'etage Bathonien du Bas 

 Boulonnais " par E. Rigaux et E. Sauvage. Mem. Soe. Academ. Boulogne, 

 1867, Yol. iii. pi. iv. fig. 4. 



