ANNIVERSARY ADDRESS OF THE PRESIDENT. XClll 



Germany. France. England. 



1. Unter-Oolith. Bajocien. Inferior Oolite. 



2. Bath-Gruppe. Bathonien. Bath Oolite. 



3. Kelloway-Gruppe. Callovien. Kelloway Rock. 



As the third part of the work has not yet been published, the 

 subdivision of the Oberer Jura cannot be at present stated. This three- 

 fold division is ingenious and practically useful, though, of course, 

 the result of such arrangements must always be a tendency to force 

 the natural grouping into a conformity with the artificial. In the 

 preface Dr. Oppel pays a just tribute of respect to the memory of 

 William Smith, who, he observes, first laid the foundation, in the 

 years 1815-16, for a correct classification of the Jura Formation, by 

 his work entitled, ' Strata Identified by Organized Fossils,' which 

 being followed by the Outlines of Conybeare and Phillips, at a time 

 when little had been done in this way in France and Germany, 

 spread the English names over the Continent, where they were 

 freely adopted, still preserving their identity in Germany ; whilst 

 in France they have been formed into French names more consistent 

 with the genius of the French language. 



In proceeding to the further subdivision of the several sections 

 of the lias. Dr. Oppel carries out the views of Von Buch, and 

 founds his subsections on the predominance of individual fossils 

 which appear to characterize each subsection. In the lower lias, 

 therefore, he distinguishes no less than eight such subsections, the 

 lowest being the celebrated Bone-bed, by which it may be said the 

 Jura Formation and the Triasic appear to be connected, if, indeed, 

 as many believe, the bone-bed should not rather be entirely allotted 

 to the Triasic. The other seven subsections are thus named from 

 below upwards : — 



1. Bed, bank, or zone of Am- 4. Bed of Pentacrinus tuber- 



monites planorbis. culatus. 



2. Bed of Ammonites angu- .5. Bed of Ammonites obtusus. 



latus. 6. Bed of oxynotus. 



3. Bed of Bucklandi. 7. Bed of raricostatus. 



Now, if we observe that the bone-bed is separated from the bed 

 or zone of Pentacrinus tuberculatus, which is the rich depositary 

 of Ichthyosauri and Plesiosauri by three other beds, and recollect 

 that the bone-bed has its own characteristic assemblage of Saurians 

 and other animals, totally distinct from those of the Pentacrinus- 

 bed, and of which some species are common to the Muschelkalk, — 

 it seems more reasonable to connect it with the trias than with the 

 lias. On this question Oppel thus observes : — " The remains of 

 Vertebrata in the bone-beds harmonize with those of the trias, and 

 this not alone in respect to genera, but also as regards species, 

 several of which have been found by Plieninger in the bone-bed 

 of the Muschelkalk of Wurtemberg ; namely, Gyrolepis Albertiy 

 G. tenuistratus, Saurichthys acuminatus, Sphcerodus minimus. At 

 the same time some species of Vertebrata occur in the lias bone- bed 



