I 



ETJBOPE. 49 



Rorschach ; 3. Mud-streams (Schlammstrome) ; soft beds crushed by 

 overlying rock move down towards valleys, like lava-streams, e. g. 

 Wiiggis in 1795 ; 4. Mixed falls (gemischte Stilrze), consisting of 

 fragments of rock, earth, and mud, e. g. Goldau and most others. 

 Recognizes in each slip three regions: 1. Origin; 2. Course; 3. Final 

 position. Refers most of the falls to water resting on clay or other 

 impermeable material, and thus loosening the base of the overlying 

 rock, which ultimately loses its hold. F. W. R. 



Baltzer, Dr. A. Ueber einen neuerlichen Felssturz am Rossberg, 



nebst einigen allgemeinen Bemerkungen iiber^ derartige Erschei- 



nungen in den Alpen. [Recent Fall of Rock at the Rossberg.] 



N. Jahrh. Heft i. pp. 15-26 ; wdth 3 woodcuts. 



Account of a fall of rock in August 1874, at the Rossberg, near 



Arth, in Switzerland. Smaller than the great fall of the Goldau in the 



same locality in 180G. The fall of the Goldau is called a Bergstui-z ; 



that of the Rossberg only a Felssturz. Also describes a fall at Bilton, 



in Glarus, in April 1868, and a landslip at Sax, near Chur, in 1874. 



Classifies slips and falls as above, and discusses the causes of such 



phajnomena. F. W. R. 



Barrels, Charles. L'Aache'nien et la limite entre le Jurassique et 

 le Cretace dans I'Aisne et les Ardennes. [The Aachenian and the 

 junction of Jurassic and Cretaceous in Aisne and Ardennes.] Bull. 

 Soc. Geol. France, 3 ser. t. iii. pp. 257-265. 



At the base of the Cenomanian in Belgium and N. France is a ter- 

 restrial deposit called the Aachenian. Three opinions exist regarding 

 its age. Gosselet calls it Gault, De Lapparent believes it to be AVealden, 

 while, according to Comet and Briart, its formation has continued from 

 the end of the Carboniferous period to that of the Gault. M. Barrels 

 shows that the Aachenian conglomerate of Aisne contains the fossils of 

 the Ammonites mammillaris zone at the base of the Gault, and that 

 this is underlain by a series of sands and clays (cendres), which may bo 

 traced laterally into clays containing Oxfordian fossils. The ferru- 

 ginous sands (Aachenian) are found all along the primary range of the 

 Ardennes ; and he therefore agrees with Gosselet in referring them to 

 the Gault ; at the same time he thinks it not improbable that the 

 original material was collected as a terrestrial deposit on the plateaux 

 of the Ardennes, and was rearranged by the waves of the Gault sea, 

 under which that region gradually sank. A. J. J-B. 



. Sur le Gault et sur les couches entre lesquelles il est com- 



pris dans le bassin de Paris. [The Gault of the Paris Basin.] 

 Ann. Soc. Geol. Nord, t. ii. pp. 1-61. 



Passing over the W. part of the basin, where the Gault is much con- 

 cealed by higher beds, the author commences with a study of the 

 country between the valleys of the Loire and Seine, in the natural 

 regions of Puisayo and Pcrthois. It is found that the classification 

 adopted in one place will not hold in others, and that there is great 

 difficulty in fixing the upper limit of the Gault and the base of the 



1^7.5. E 



