33o SCIENCE PROGRESS. 



immediately overlaid by those marls with Belemnites latus 

 which in the South-west of Europe also overlie the Tith- 

 onian, and are there known as Valenginien. Tithonian 

 beds also occur to the west of Theodosia, and the series 

 appears to be well developed in the Crimea. 



CRETACEOUS. 



The occasional patches of Jurassic rocks which have 

 already been referred to, in the North German plain, occur 

 principally around the mouth of the Oder. Farther to the 

 west, and stretching as far as the Elbe, there appear through 

 the drift a number of small patches of Cretaceous. One of 

 these, near Liineberg on the Ilmenau, has long been sup- 

 posed to include representatives of the Gault in the form of 

 a clay with Belemnites minimus. The clay is conformably 

 succeeded by a limestone which passes up into sandstone 

 with Ammonites rotomagensis (upper Cenomanian). Von 

 Strombeck (36) after a close examination concludes that the 

 belemnite is Belemnites ultimus. It is associated with Ser- 

 pula (Vermicitlaria) Soiverbyi; and both of these are Cen- 

 omanian forms. Hence he refers the whole series up to the 

 rotomagensis beds to the Cenomanian, and places the clay at 

 the base as the representative of the Tourtia or lower division. 

 No Gault is present ; and the author maintains that the re- 

 ference to the Gault of other exposures in this neighbourhood 

 rests upon similar incorrect determinations. This is a point 

 of some importance ; for it is certain that the Cenomanian 

 sea was much more extensive than that of the Gault, and if 

 there has been no Gault here, the sea of that period must 

 have been even smaller than has been supposed. 



To the west of Glatz on the borders of Bohemia and 

 Prussian Silesia, a long elliptical patch of Cretaceous rocks 

 rests unconformably upon the older rocks of the Sudeten- 

 gebirge. It is now entirely separated from the Cretaceous 

 of the North-east of Bohemia ; but it evidently belonged to 

 the same sea-basin, and between the two areas lie a number 

 of small outliers bearing witness to their former union. 

 One of the most extensive of these outliers is that of 

 Cudowa, which has been examined in detail by Michael (23). 



