146 Mr. J. Lycett on the so-called Sands 



lunuJaris, Modiola ungulina, Gresslya abducta, and Modiola com- 

 pressa. The upper zone contains in addition the following 

 Oolitic species : Cypricardia cordiformis, Hinnites abjectus, 

 Astarte excavata, Sow., var., A. detrita, Macrodon Hirsonensis, 

 Modiola Sowerbii, Gervillia Hartmanni, Gresslya conformis, 

 Homomya crassiuscula. Pecten textorius and Turbo capitaneus 

 appear to have a considerable stratigraphical range, as they are 

 found from the Upper Lias to the Inferior Oolite inclusive. Of 

 the eighteen Ammonites, which appear to include fifteen distinct 

 species, several are undoubtedly derived from forms which occur 

 in the higher beds of the Upper Lias shale of the counties of 

 York and Somerset ; others seem to be proper to the stage, and 

 not one of the Ammonites passes upwards into the Inferior 

 Oolite. The Brachiopoda appear to be entirely Liassic deriva- 

 tives ; and even Rhynchonella cynocephala, which, from its abun- 

 dance and wide diffusion, seems to offer a good designation for 

 the stage (Cynocephala-stage), is perhaps nothing more than a 

 variety of R. acuta, the number of plaits, whether anterior or 

 lateral, affording no constant or reliable distinctive character ; 

 in other respects the general figure of both is absolutely the 

 same. The single Nautilus, N. latidorsatus, is also Liassic. On 

 the other hand, in the numerous Conchifera the Liassic element 

 nearly disappears altogether, and we find a considerable infusion 

 of the Oolitic, leaving, however, no inconsiderable number of 

 species which appear to be proper to the stage. It is indeed a 

 very striking but undoubted fact, that of the very numerous 

 Liassic Conchifera and Gasteropoda, not more than four or five 

 are continued into the Cynocephala-stage, and even of these 

 two only are found in the upper zone. The more common 

 Upper Lias Ammonites (Lias Epsilon) are equally absent in the 

 Cynocephala-stage, as A. communis, A. serpentinus, A. bifrons, 

 A. annulatuSj A. exaratus, A. elegans, Y. & B., A. fimbriatus. 

 A. striatulus is strictly identical with the Liassic form ; but the 

 common Cotteswold form of A. variabilis var. dispansus offers 

 well- marked distinctions from the Liassic variety, which, as it is 

 the A. Beanii of Simpson, may be termed the variety Beanii. 

 The variety dispansus is more compressed, the volitions more 

 enveloped; both the fasciated tubercles and the ribs are smaller, 

 less prominent and more numerous ; the ribs being much more 

 curved near to the keel. The Liassic variety, however, occurs very 

 rarely at Frocester Hill. Ammonites opalinus I have omitted 

 altogether, as the single specimen found lying upon the ground 

 at Haresfield Hill may have been derived from those superin- 

 cumbent Inferior Oolite beds to which it has been referred by 

 Quenstedt and Oppel. The species alluded to is the opalinus of 

 Keinecke, Zieten, and Quenstedt, but not the priniordialis of 



