" UPPER-LIAS CLAY " OF DOWN CLIFFS. ■ 521 



be here noticed. In 1865 * and subsequently t Brauns ends the 

 Lias with the Amaltheus-zone t ; he unites as "Toarcian" " Der 

 obere Lias und unterste braune Jura " § ; he also speaks of this 

 as the " Palciferenschicht " II ; and he commences the " Unteroo- 

 lith " with the " Coronatenschicht " %. Branco ** states that in 

 Alsace-Lorraine the Lias ends most naturally with the zone of 

 Amaltlieus costatus ft, and he finds no sharp line of division from 

 the Posidononiya--heds until the zone of Harpoceras Soiverhyi XX. 



Hang §§ says that the zones of Opalinum and Jurense are so 

 closely united by what are practically the same species that one 

 cannot draw the line separating Lias and Oolite as the Germans 

 wish ; further, that the zones oi MurcMsonce and Opalinum are quite 

 as closely connected || ||, and he is of opinion that, from a palaeonto- 

 logical point of view, the division at the base of the Sowe?'byi-zone 

 is the most practicable %%. 



These opinions are worthy of attentive consideration. When the 

 views of d'Orbigny, Deslongschamps, Yacek ***, and Lepsius ftt are 

 added to the above, and also the facts which Hudleston XXt so 

 constantly impresses upon us concerning the difference between the 

 Upper and Lower divisions of the Inferior Oolite, it will be seen 

 that there is a very strong case in favour of a division like the 

 Toarcian. 



Discussion. 



Mr. H. B. WooDWAED observed that Mr. Day had, in 1863, first 

 described in the Down Cliffs a band of limestone forming the junction 

 of Middle and Upper Lias. The lower portion, an ironshot-limestone 

 (Marlstone), yielded Ammonites spinatus and A. crassus, and the 

 upper i)ortion, a pale limestone, A. hifrons ; while, common to both 

 portions, Mr. Day found A. communis, A. Ifolandrei, A. serpentinus, 

 and A. radians. He had himself found A. striatidus in the base of 

 the Upper Lias at Down Cliffs and at Allington near Bridport. The 

 same lithological characters and stratigraphical succession, and the 

 same assemblages of fossils, characterize the Marlstone and the base- 

 ment-beds of the Upper Lias from Dorsetshire to Lincolnshire. He 



* " Die Stratigrapbie und Palaontologie des siidostlichen Theiles der Hils- 

 mulde," Palseontographica, xiii. 



t Untere Jura in NordwestHchen Deutschland, 1871. 



+ Die Sti-atigraphie, p. 85. § p. 87. || p. 89. 1j p. 90. 



-X-* " Untere Dogger," Abband. zur geoL Spez.-Karte Elsass-Lothringen, Bd. ii. 

 Heft i. 1879. 



tt p. 141. ++ p. 140. 



§§ " Polymorphidae," Neues Jahrbuch fiir Mineralogie, &e., Bd. ii. 1887, 

 p. 161. 



I II Compare my remarks, p. 520. 



*f[^ Haug would extend the Lias to this point, as Vacek wishes ; but I prefer 

 the division Toarcian for the period dominated by the Hildoceratidm or the 

 Falciferi. 



"^^'^ Q,uart. Journ. Geol. Soc. vol. xlv. p. 466. 



i'tt Eeitrage Jurass. Unter-Elsass, 1875. 



\\X Inf.-Oohte Gasteropoda, Pal. Soc, vol. xl. p. 26 et seq. 



Q. J. G. S. No. 183. 2 p 



