part 1] GAULT AXD LOWER GEEEKSAIN^D ISTEAR LEIGHTOST. 73 



Woods notes ^ that the species, for which English material is scanty, ' closely 

 resembles P. striato-punctatus Romer,' a shell of wide range in the Lower 

 Cretaceous and doubtfully present in the Gault of Folkestone, where it is 

 recorded by Price as occurring in the ' Junction Bed ' VIII. "-^ The Shenley 

 shell may be found to correspond to the Gault form. 



(ii) Cyprimeria rotomagensis, ' a species of the basal Cenomanian of Wiltshire ' 

 (K.P., p. 5), is, I believe, a somewhat doubtful determination. It is, at the 

 best, a rather featureless shell, and is usually preserved as casts. The genus 

 has two species in the Lower Greensand of the Isle of Wight, one of which, 

 C. parva, is near to this form. The known range of the genus in the English 

 Cretaceous rocks is from the Atherfield Beds to the Lower Chalk.^ 



(iii) Isoarca ohesa, ' which is not known elsewhere from below the Chloritic 

 Marl ' (K.P., p. 5). This species is regarded as synonymous with Tsocardia 

 orhigmjana A. d'Archiac, occurring in the Flemish Tourtias.'' A. J. Jukes- 

 Browne, in his General List of Chalk Fossils,^ marks it as ' found in 

 Selborniaii,' but does not include it in the ' Selbornian ' List in his previous 

 volume,^ where the only species mentioned is Isoarca agassizi P. & E. Pre- 

 suming that the identification is unquestionable, the presence of the species 

 at Shenley increases its hitherto known range. 



(iv) Lima glohosa. Since the downward range of this fossil through the Gault 

 is admitted, it seems beside the mark to note that ' the type .... came from 

 the Chloritic Marl ' (K.P., p. 6). The Lower Chalk is the limit of its upward 

 range. The species is recorded by Price ' from near the bottom of the Lower 

 Gault (Bed II) at Folkestone. Mr. Woods ^ remarks that it ' closely resembles 

 Lima alhensis d'Orbigny,' a species mentioned by Prof. C. Barrois ^ as occurring 

 in the Mammillatus Beds as well as in the Lower Gault of the North of France. 

 There is nothing incongruous in the presence of Lima glohosa in the Shenley 

 limestone. 



Dr. Kitchin & Mr. Pringle bring also into the argument two species of 

 small oyster, which I found in the wedge of greensand in Garside's pit 

 (pp. 10-12), believed by them to be inverted ' Upper Greensand.' They mention 

 them as 'well-developed valves of Ostrea vesimlaris Lamarck, such as are 

 ' found in the zone of Pecten asper Lamarck ; also Ostrea canaliculata (J. 

 ' Sowerby), a species which occurs much more commonly above the Gault than 

 'below it' (K.P., p. 6). But both species, believed by Woods to be allied,^^ 

 begin their long range in the Lower Greensand, 0. canaliculata being found 

 as low as the Hythe Beds, so that their presence below the Gault, whenever 

 conditions favoured their growth, might be anticipated and certainly needs no 

 abstruse explanation. 



On the other hand, the absence, so far as known, of the commonest 

 oysters of the Upper Greensand, 0. vesiculosa and Exogyra conica, is awkward 

 to explain on the overturn-hypothesis. 



As for the limestone, if it were ' Cenomanian,' we ought to find in it some 

 of the commoner lamellibranchs of the period ; as, for example, Pecten asper, 

 P. heaveri, Lima aspera, L. elongata, Pholadomya decussata, etc. ; all, as yet, 

 missing. 



1 Ihid. vol. i. pt. 4, p. 161 (1902). 



2 ' The Gault ' p. 56. 



3 H. Woods, op. cit. vol. ii, pt. 9 (1913), Tables, pp. 439, 447. 



4 Ihid. vol. i, pt. 1 (1899) p. 65. 



'" ' The Cretaceous Eocks : vol. iii — The Upper Chalk ' Mem. Geol. Surv. 

 1904, p. 477. 



6 'The Cretaceous Eocks : vol. i— The Gault. &c.' Mem. Geol. Surv. 1900, 

 p. 467. 



7 ' The Gault ' p. 54. 



^ Op. supra cit. vol. ii, pt. 1 (1904) p. 17. 



^ ' Terrain Cretace des Ardennes ' Ann. Soc. Geol. Nord, vol. v (1878) p. 274. 



Op. supra cit. vol. ii, pt. 9 (1913) pp. 360-78. 



