PORTLAND EOCKS OF EXGLAXD. 209 



Section north of the Road to Coate. 



ft. in. 



a. Calcareous sands, with hard block (as in great 



quarry) 8 



b. Cardium- and Trigonia-h&A 3 8 



c. White chalky rock, with Cardia 1 2 



d. Limestone brash, with Trigonice 2 6 



e. Glauconitic limestone, in two beds 2 



There cannot be the slightest doubt, then, that these beds succeed 

 those of the great quarry in a downward direction. The supposition 

 that they corresponded to the beds overlying the " basal sands '' has 

 led to the introduction upon the map, at this spot, of a fault which 

 does not exist. This quarry forms part of a slight synclinal fold ; 

 for on the other side of the road is another, in which the beds dip 

 to the north. This shows the same succession — the " basal sands " 

 at the top and the remainder of the beds below, the last becoming 

 very argillaceous. There is some doubt whether the glauconitic 

 bed ought not to be separated from the rest, though it doubtless cor- 

 responds to the base of Xo. 3 at Swindon. These quarries show a 

 very interesting fauna, as in the following list : — 



Fossils of the Trigonia-6g<:?s near Sivindon. 



c. Ammonites boloniensis {Be L.). 



pectinatus {Ph.). 



Boisdini {De Lor.). 



Pleurotomaria rugata {Ben.). 



Natica elegans {Sow.). 

 c. Trigonia gibbosa {Sow.). 



Yoltzii {Ag.). 



incurva {Ben.). 



(ine) Carrei {Mun. Chal.). 



(in c) Cyprina elongata {Blake). 



Cypricardia costifera {Blake). 



Anisocardia pulchella {DeLor.). 

 Cardium dissimile {Sow.). 

 Lucina portlandica {Sow.). 

 Pleuromya tellina ( Volts). 

 Thracia tenera {Ag.). 

 Mytilus unguiculatus {Phill.). 



boloniensis {Be Lor.). 



pernoides {Bom.). 



Lima rustica {Sotv.). 



ornata {Btiv.). 



Pecten lamellosus {Sow.). 



The qnarry to the east of the reservoir reaches to the upper part 

 of these beds, having Xo. 2 overlying. It is characterized by the 

 abundance of Ammonites, Pecten, and Pleuromya, as above. 



The outlier at Bourton (Pl.YIII. fig. 6) shows, for the most part, a 

 continuation of these beds. In the southern quarry little but loose 

 sandy limestones, with very few fossils, are seen. These no doubt cor- 

 respond to the " basal sands " of KSwindon. The only fossil actually 

 seen was Trigonia gihhosa ; but both this and Ammonites become more 

 abundant towards the top. In another quarry in the village, the suc- 

 ceeding rubbly beds are full of various fossils — Pleurotomaria rugata, 

 Pecten lamellosus, Trigonia gihhosa, Cardium. Pellati, Cyprina swin- 

 doncnsis, &c. The most noteworthy feature is the abundance oiEchino- 

 hrissus Brodiei, vrhich, like all other Portlandian urchins, is elsewhere 

 so rare. The Cardium, recorded also by^I. Saemann from Swindon, 

 and compared by M. De Loriol, is distinctly different from C. dissimile, 

 and belongs to the lowest true Portland beds at Boulogne ; and the 

 Cyprina is found at a lower horizon at Swindon. Besides these are 

 many Ammonites not seen in situ — A. boloniensis, A. hiplex, and a 



