Reviews — C. Stfuckmann — The Upper Jura of Hanover. 225 



(this last containing epidote in place of hornblende) ; and the nephelitic species 

 Zircon-Syenyte, Foyayte. 



IV. The Hornblende and Soda-Lime Feldspar Series : including Dioryte 

 (with Propylyte), Andesyte, Labradioryte (or Labrador-dioryte), etc., and the 

 saussurite rock, Euphotide. 



V. The Pyroxene and Potash Feldspar Series : including Amphigenyte. 



VI. The Pyroxene and Soda-Lime Feldspar Series : including Augite- 

 Andesyte, Noryte (Hypersthenyte and Gabbro in part), Hypersthenyte (containing 

 true hypersthene) , Doleryte (comprising Basalt and Diabase), Nephelinyte, etc. 



VII. Pyroxene, Garnet, Epidote and Chrysolyte Rocks, containing 

 little or no Feldspar: including Pyroxenyte, Lherzolyte, Garnetyte (Garnet 

 rock), Eclogyte, Epidosyte, Chrysolyte or Dunyte (Chrysolite rock), etc. 



VIII. Hydrous Magnesian and Aluminous Rocks, containing little or 

 no Feldspar : including Chlorite schist, Talcose schist, Serpentine, Ophiolyte, 

 Pyrophyllite schist, etc." 



P 



III. — A New Order of Extinct Eeptiles. 



EOF. 0. C. MARSH has recently described 1 a genus of reptiles 

 from the Jurassic formation of the Eocky Mountains, which he 

 considers to represent a new extinct order — the Sauranodonta. The 

 genus Sauranodon is closely related to Ichthyosaurus, and presents, 

 in most of its skeleton, the characteristics of that genus, but is 

 without teeth. The vertebrae, ribs, and other portions of the skeleton 

 preserved cannot be distinguished from the corresponding parts of 

 Ichthyosaurus, and many features of the skull show a strong re- 

 semblance. The great development of the premaxillaries, the 

 reduced maxillaries, the huge orbit defended by a ring of bony 

 plates, are all present, but the jaws appear entirely edentulous, and 

 destitute even of a dentary groove. This genus Sauranodon, from 

 the absence of teeth, bears a similar relation to the Ichthyosaurs 

 that Pteranodon does to the true Pterodactyls, and it is interesting 

 to find the two highly specialized forms preserved in the same region. 



J. M. 



EEVIE W S. 



I. — Der Obere Jura der Umgegend von Hannover eine Pal^eon- 

 tologisch-geognostisch-Statische Darstellun g, von C. Strtjck- 

 mann. (Hans'sche Buchhandlung, Hannover, 1878.) 



WHILST the English Oolitic rocks are remarkable for the num- 

 ber of their beds and the organic richness of their contents 

 in the Lower and Upper Middle divisions of the series, the Oxford- 

 clay, Kimmeridge-clay, and Portland beds have not yet afforded 

 corresponding results to the palaeontologist, and the student of 

 Jurassic Geology has therefore to turn his investigations into other 

 regions in order to obtain an insight into the condition of the shore 

 life of Oxfordian, Kimmeridgian, and Portlandian strata. 



We therefore welcome the appearance of Herr. Struckmann's 

 beautiful Monograph on the Upper Jura of Hanover, and recom- 

 mend its careful study to all students of Jurassic Geology. The 

 formations described in this work are the Oxford ; Coralline Oolite, 

 1 American Journal of Science and Arts, vol. xvii. p. 85, January, 1879. 



DECADE II. VOL. VI. — NO. V. 15 



