212 



EEV. J. P. BLAKE ON TKE 



Fossils of the Portland Sand, Swindon. 



Ammonites biplex (Sow.). 

 c. pectinatus (Ph.). 



Alaria Thurmanni (Cont.). 



Cerithium Lamberti (De Lor,), 

 c. Turbo Foucardi (Cott.). 



Delphinula globosa [Buv.), 



Pleuromya Voltzii {^g.). 



Plectomya rugosa (Bom.), 

 c, Pholadomya tumicla {Ag.), 



Sowerbya loBgior [Blake). 

 c. Astarte polymorpha {Cont.). 

 ^ Samanni (De Lor.). 



Myoconcba portlandica {Blake). 



Ssemanni {Lollf.). 



Cyprina swindonensis {Blake). 



pulchella {Be Lor.). 



Lithodomus, sp. 



Lucina fragosa {Be Lor.). 



Cardium Morinicum {Be Lor,). 



c. Trigonia Pellali {Be Lor.). 



swindonensis {Blake). 



Area velledse {Be Lor.). 



Mytilus autissiodorensis {Cott.). 



longsevus {Cont.), 



boloniensis {Be Lor.). 



Perna Bayani ? {Be Lor.), 

 c. Bouchardi {Opp.). 



Pinna suprajurensis (!?' Orb.). 



Lima boloniensis {Be Lor.), 

 c, Pecten Morini {Be Lor.). 



suprajurensis {B'Orh.), 



solidus {Bom.), 



Placunopsis Lycetti {Be Lor,). 



Ostrea bononias {Be Lor.) ? 



rxivi\Xiiovm\s{Koch ^ Bunk.). 



Exogyra bruntrutana {Thurm.). 

 * Acrosalenia Kcenigi {Besm.). 



More, perhaps, of these are new than the list would indicate ; 

 hut whatever names are assigned, the fauna itself is very distinct 

 from that of the Portland rock. Trigonia gihhosa has not yet 

 arrived, nor even Cardium dissimile. Many of the forms are cha- 

 racteristic of the so-called middle Portland of Boulogne or of the 

 highest " Portlandian " beds of other districts. Indeed the relations 

 are closer to the Kimmeridge Clay than to the Portland Stone ; yet 

 the stone most certainly belongs to the Portland Sand, and cor- 

 responds to lios. 11, 12 of the typical section, with which it shows a 

 wonderfully close agreement. At Bourton the bed beneath the 

 conglomeratic rock is just like the top of this at the north of 

 Swindon, and contains Pecten Morini and Pholadomya tumida. 



Up to the present day there has scarcely been known a particular 

 fauna for the Portland Sand. It has not been separated palaeonto- 

 logically from the Stone ; and the fossils quoted from it are often 

 those of the basal bed of the latter. In Dr. Pitton's list, which is 

 still the longest, the only named species which do not also occur in 

 the Stone, are two Serpuloe, a Lima, Trigonellites, and Ostrea solitaria. 

 In Prof. Phillips's list Hemicidaris Davidsoni is the only one ; but, 

 in reality, many of his additions belong, in all probability, to this 

 horizon, though quoted as from the Stone. Such, for example, must 

 be his Pecten nitescens {=P. solidus)., Pinna lanceolata ( = P. supra- 

 jurensis), Modiola jpectinata {^^Myt. autissiodorensis), Pholadomya 

 rustica and incequalis {=P' tumida), and Amtnonites pectinatus 

 (which is the same as A. Devillei, De Lor. ; but Phillips's name has 

 the priority). The present list, with those that occur in Dorset- 

 shire, will, to a certain extent, supply the deficiency. 



No. 6. A series of loose yellow-grey or white sands, with enor- 

 mous doggers, some at the top being a compact calc-grit, with Tri- 

 gonia Pellati and Pleuromya Voltzii, some nearer the bottom being 

 glauconitic and more fossiliferous, with Pernce a] so. Below these 

 * Found by Mr. Hudleston. 



