POSITIONS OF THE TRIG02fIiE OF NOETH OXFOEDSHIEE, ETC. 41 



Yorkshire specimen in my cabinet. There is also a general tendency 

 to an upward curvature of the rows of costce, which places it in near 

 relationship to T. formosa, from which, however, it differs in the 

 marked isolation of the tubercles anteally and their evanescence in 

 its lower half. 



Teigoxia ^JtloRETONi, var. oxoNiENsis, Mor. & Lj'C, seems to be 

 confined to the beds C of Hook Norton and Otley Hill. Young forms 

 of T. angulata are difficult to distinguish from this little shell. T, 

 Moretoni, according to Etheridge, is found rarely in the Collyweston 

 Slate, and in the lower zone of the Great Oolite it seems to be well 

 known generally. 



Trigonia AN6TJLATA, Sow., occurs not uncommonly in and imme- 

 diately above the coral bed (C) at Hook Norton and Otley Hill, and 

 also at the bed at the base of the Clypeus-grit (C^) at Pawler and 

 Bright Hill. The ornamentation of the species is very variable. 

 Lycett and Witchell cite it from the Oolite Marl, and also from the 

 various beds of the zone of Ammonites Paricinsoni in Gloucestershire. 

 Trigonia clapensis of Terquem and Jourdy*, from the ^'Paricin- 

 soni " zone of the basin of the Moselle, appears to resemble very 

 closely some Oxfordshire forms I have classed as varieties of T. 

 angulata. According to Lycett T. clapensis is a synonym for 

 T. Moretoni. 



Trigoi^ia Gtjisei, Lye, appears to belong only to the base of C. 

 I have a large specimen, measuring three inches in height, found in 

 situ in the bottom bed of the Duckpool-Earm cutting, where the 

 lower zone of the Inferior Oolite is wanting. This caused Dr. 

 Lycett to refer it in error to the "lower beds of the formation." 

 Its Oxfordshire horizon is in reality that of the Lower Trigonia-grit. 

 The species is allied to T. Paricinsoni, Ag., and T. angulata, Lye. 

 Mr. AVitchelL's specimens, which I think should scarcely be classed 

 with the Oxfordshire shell, are from the Clypeus-grit. 



Trigonia peoducta. Lye, finds its home in the Hook-Norton area. 

 Though appearing in the Coral bed, it is better showm in a higher 

 band of ironshot limestone (no. 22 of my detailed section t), also in 

 series C. At the base of the Clypeus-grit (C^) at Pawler, at Bright 

 HiU near Long Compton, and in the siliceous limestone of the Tri- 

 gonia-bed at Sharpshill it occurs also. Under a modified form it 

 again appears at the base of the Fuller's Earth J: in a railway- cutting 

 near Bourton-on-the- Water, Gloucestershire. The test there is 

 thinner than that of the Oxfordshire T.producta, and in its ornamen- 

 tation as well as contour it approaches T. Painei, Lye, an abundant 

 shell in the stratum on which the clays of the EuUer's Earth rest. 



* " Monographie de I'etage Bathonien dans le departement de la Moselle," par 

 O. Terquem et E. Jourdy. Mem. Soc. Geol. de France, 1869. 



t " On the Eelation of the so-called ' Northampton Sand ' of North Oxford- 

 shire to the Clypeus-grit " (Quart. Journ. Geol. Soc. vol. xxxix. p. 230). 



J Derived probably from the stratum below. Forms more nearly referable 

 to T. suhglohosa. Lye, are there associated with T. Fainei. A similar shell 

 occurs in series C at Hook Norton. 



