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thickness, (No. 6 in section,) in whicL I failed to find any organic remains ; 

 but the rapid decomposition of the iron pyrites, disseminated through the 

 shales, on exposure to atmospheric influences, is so powerful an element 

 of destruction, that fossils are rarely found in beds of this character, 

 unless the shales are deeply cut into. The succeeding bed of hard dark 

 grey micaceous Sandstone (No. 7,) is a conspicuoiis and prominent feature 

 along the face of the cliff, especially near the centre of the section, standing 

 out in a step-like ledge beneath the superincumbent mass of black and 

 dark Cardium shales. The upper siirface of this thick Sandstone is 

 ripple marked, the I'ippled gi'ooves being nearly at right angles to, or lying 

 across the direction of the dip of the bed ; in other words, they are 

 parallel to the strike of the beds on which tliey occur. "With little 

 variation, this zone measures 12 inches in thickness, but has, like No. 5, 

 a parting near the base, dividing it into two portions. This well-defined 

 hoi'izon in the cliflT has been, and is well designated, the Pullastra Bed or 

 Zone, from its being so crowded with the casts of that ubiquitous and 

 cosmopolitan shell, Pullastra arenicola, Stiickl. ; for, at every section 

 where these beds are exposed, it is ever present, and in the same position, 

 thus determining the range in time and space these beds occupy; and the 

 same remark may apply equally well, to the Avicula contorta, Portl., and 

 Cardium Rhceticum, Merian., of this group of rocks. Coprolites and 

 Fish Scales occur at the base, or in the lower part of the bed, below the 

 parting, thus relatively occupying the same position as in the thinner 

 Pullastra bed below (or Micaceous Fish Bed, No. 5, bottom part.) 

 Fresh fractures along the plane of bedding or deposit, reveal the species : — 



Cardium Ehfeticum, Merian. 



Modiola minima, Soiv. 



Avicula contorta, Portl. 



Pullastra arenicola, Strickl. 



Axinus or Schizodus, 

 the Pullastra being the most numerous, but all chiefly occur in the fonn 

 of casts, though well defined. The weathered surfaces of fallen slabs, or 

 tabiilar blocks from the same bed, strewn over the shore, also shew the 

 same species clearly defined, with other indeterminate and equivocal 

 forms. This bed is, and will always present an important horizon in the 

 structure of the cliff, one recognisable by all, and constitutes a good 

 datum line for measuiements, and a clear starting point for the succession 

 of the beds above or below ; as well as afibrdiug data for the corre- 

 lation of these beds on the same horizon in other and distant sections in 

 Gloucestershire and adjacent counties; but in the character of a hard and 



