264 J. F. BLAKE AND W. H. HUDLESION ON 



mouth, Ammonites perarmatus (Sow.), Belemnites abbreviatus (Mill.), 

 Ostrea dilatata (large var.), Turbo Meriani (Goldf.), Myacites jurassi 

 (Brongn.), and Lucina, sp. (cf. lirata). Traced westward from Osming- 

 ton, these grits are thinning out, till at Broadwey, due north of Wey- 

 mouth, they are scarcely discoverable, unless represented by a single 

 2-ft. block of ferruginous sandstone, lying in the midst of clays ; and 

 only a thin band can be identified in the valley south of Abbots- 

 bury, which is excavated down to the Oxford Clay. This restric- 

 tion of the deposit is a feature worthy of attention. 



The series of beds which follow the jNothe Grits are again argil- 

 laceous, though containing bands of hard calcareous grit towards 

 the base. We include in this series, which we call the " jSTothe 

 Clays," about 40 ft. of beds at Weymouth, which are spread out in 

 the bay to the south of the town. They are of less thickness in 

 the other localities ; but they present no particular feature, except at 

 Wyke, where they are separated from the Nothe Grits by a few feet 

 of a fissile calcareous sandstone, surmounted by rubbly limestone 

 with fragments of shells — the debris possibly from some coral-reef 

 to the west, now removed from our sight. These usurp the place of 

 some of the lower grit bands at Weymouth. 



The fossils from the Nothe Clays are : — 



Ammonites cordatus (Sow.). 

 Nautilus hexagonus (Sow.). 

 Alaria trifida (Ph.). 

 Cucullsea contracta (Ph.), ^ar. 

 Area aemula (Ph.). 

 Trigonia perlata (Ag.). 

 Perna quadrata (Sow.). 

 Thraoia depressa (Sow.). 



Modiola bipartita (Sow.). 

 Lima elliptica (Whit.). 

 Pecten fibrosus (Sow.). 

 Anomia radiata (Ph.). 

 Exogyra nana (Ph.). 

 Ostrea dilatata (Sow.). 



gregaria (Sow.). 



Serpula tricarinata (Sow.). 



It is interesting to note that this list has on the whole more of an 

 Oxfordian than of a Corallian type, very few of the more peculiar 

 forms of the latter appearing in it — a proof that in this district 

 at least the fauna of the sands and grits makes its appearance rather 

 on account of physical changes than on account of the lapse of time. 

 We can scarcely find a parallel to this reiutroduction of clay else- 

 where, unless it be in the Clays overlying the Elsworth rock. 



Succeeding to these Clays is another series of Grits and Sands, 

 which from their being well developed at Bencliff, east of Sandsfoot 

 Castle, we call the " Bencliff Grit Series." They consist here, in 

 descending order, of 



1 . Calcareous grit, with dichotomizing branches, 



very hard in the upper pari, passing down into 

 softer calcareous sands, with a band of compact 

 argillaceous limestone at the base 10 



2. Sandy shales, becoming loose " foxy" sands, which 



contain towards the base huge tabular doggers of 

 indurated calcareous sandstone 11 



The first bed alone is fossiliferous, and that only locally, the 

 remarkable feature of the series being the large doggers of the 

 lower sands. These are due to the subsequent action of mineralized 

 waters, which, percolating through the luoso sands, were stopped 



