378 Reviews — Mexican Ammonites. 



The authors consider that towards the close of the Cretaceous period 

 a general rise of the land took place in northern Europe, the Danian 

 being deposited in the south and west part of the Baltic. At the 

 beginning of the Palaeocene epoch they think that this sea of the 

 North German plain entered into free communication with the sea 

 over South Russia, which spread to meet it from south-east towards 

 the north-west and north. Still later the western ocean overspread 

 the Anglo-Parisian basin, thus entering into communication with the 

 Eocene sea of the West Baltic and North Germany. During the 

 same epoch rises of land towards the east completely severed the com- 

 munication between the sea of South Russia and that of the "West 

 Baltic. 



The Palaeocene fauna described in this memoir is very different from 

 that of the Thanet Sand, and is probably older. It is not clear why 

 the authors consider that this Palseocene sea and the Danian sea did 

 not extend across Britain. The fauna of the Trimingham Chalk shows 

 us that the absence of the higher zones over most of Britain is only 

 due to denudation. Why should not the same cause account for the 

 absence of the earliest Eocene deposits? 



C. R. 



III. — Mexican Ammonites. 



rpHE Institute Geologico de Mexico has recently published Boletin 

 J_ Numero 23 (dated 1906), "La Faune Jurassiqiie de Mazapil, avec 

 un appendice sur les fossiles du Cretacique Inferieur, par le Dr. Carlos 

 Burckhardt" (13 by 9^ inches), in 2 parts, text 216 pages, 43 plates. 

 Fiftj^-nine speciesof Ammonites aredescribedfrombedsof Kimeridgian 

 age, including Oppeliaflexuomcostata, QM?it. ,Aspidoc('rasconfemporaneum, 

 E. Favre, Aspidoccras bispitiostim, Qust., sp., Idoceras [Perisphindes) 

 laxevolutum, Font., sp., Idocer as Baldemm, Om^el, sp., Haphceras Fialar, 

 Oppel, sp., Aspidoeeras avellanoides, Uhlig. Twenty-six species of 

 Ammonites are described from beds of Portlaudian age, including 

 Phylloceras apenninicum, Canavari, Perispliinctea Nihitini, Michalski, 

 Aspidoccras cyclotum, Steuer. Forty-six new Jurassic (Kimeridgian 

 or Portlandian) species are described, and eleven species of Ammonites 

 from the Lower Cretaceous. The plates from photographs have been 

 beautifully executed by Werner & Winter, of Frankfort o/M. 



B. H. 



IV. — Summary of Progress ov the Geological Survey of Great 

 Britain and of the Museum of Practical Geology for 1907. 

 pp. iv, 175, with 1 plate and 8 text - illustrations. Londonj' 

 printed for H.M. Stationery Office, 1908, Price \s. 



WE have received from the Board of Agriculture and Fisheries the 

 above-mentioned memoir of the Geological Survey, which has 

 been issued somewhat earlier than was the case with the volume for 

 the previous year. It contains, as usual, particulars of the field-work 

 carried on in different parts of England, Wales, and Scotland. 



In two districts of England the Survey has been occupied. (1) In 

 Cornwall, where the eruptive rocks of the Lizard have engaged special 



