Notices of Memoirs — Singleness of the Ice Age. 13 L 



Bed 3 is again exposed in two little sections a few feet liigh, about 

 twenty yards further west. These yielded specimens of Turritella. 



Beds 4, 6, and 8. These three beds are like each other, and in 

 composition resemble closely the last bed and beds 5, 7, and 9, but 

 differ from them in their structure, which is hard and diflScult to 

 break with the hammer, owing to the rock immediately beneath the 

 hammer-head becoming pulverised and acting as a cushion to the 

 rest of the mass. Moreover, it does not break along bedding-planes 

 {though the existence of these can be seen on a weathered surface), 

 but into irregular lumps. These beds are conspicuous on the face 

 of the section, for being harder they weather back less quickly than 

 those above and below them. They contain traces of fossils, and 

 a cast of Thetis minor, Sowerby, was found in a fallen block from 

 one of them, lying in the bog beneath the section. 



Beds 5, 7, and 9. These beds are like the last in composition, 

 only not indurated, but rather sticky and coherent. No fossils were 

 found in them. 



Bed 10. This bed ushers in sandy conditions again, being really 

 a passage bed between this zone and the zone of Schlcenbachia 

 rostrata above, which consists of slightly loamy sands throughout, 

 its base being marked by the lowest layer of Cowstones. As this 

 layer is approached, bed 10 becomes more sandy, being more 

 argillaceous in its lower part and containing a few fossil worm-tubes. 

 In places it is characterised by small bright patches of blood-red 

 iron oxide. 



To sum up : — On the face of Black Ven the total thickness of the 

 zone of Hoplites interriiptus is about 38 feet, and lies between 

 315 feet and 353 feet above sea-level. The whole is seen in two 

 sections. The beds are loams with varying proportions of sand 

 and clay. They are sandiest at the top, becoming more argillaceous 

 on descending, the predominance of the clay reaching a maximum 

 in bed 3, at about 15 feet from the base of the zone. The bottom 

 few inches of the zone also contain much clay, and are characterised 

 by an impersistent pebble bed. Fossils occur sparingly throughout 

 the zone above bed 3, but become abundant at the base of this bed, 

 simultaneously with the maximum amount of clay. The bottom 

 two beds may represent the zone of Acanthoceras mammillatum, but 

 there is not a particle of fossil evidence to justify the assertion. 



I. — Singleness of the Ice Age. 



(Die Einheitlichkeit der Quaktaren Eiszeit. Von E. Geinitz 

 in Rostock. Aus dem Neuen Jahrbuch fiir Mineralogie und 

 Palaeontologie. Beilage-Band xvi, S. 1-98. Stuttgart, 1902.) 



HE who attempts to collect, harmonize, and arrange into a scheme 

 of classification the accounts of the North European Drift 

 in separate areas is confronted with divergence of view in every 

 direction. The number of Glacial and Interglacial periods, their 



