Revieios — Dr. Paul Choffat — Jurassic Fauna of Portugal. 325 



softness of outline and gradation of tone to which their beauty is 

 due, renders it very difficult in many cases to make out details of 

 structure, especially in the teeth. 



Mr. Lydekker is paying a second visit to La Plata, and we 

 can only hope that he will make further contributions to our 

 knowledge as valuable as those contained in the present work, and 

 will treat the Edentata and Marsupials as he has here done the 

 Ungulates. 



II. — Description de la Faunb Jurassique du Portugal. Classe 

 DES Cephalopodeis. Par Paul Choffat. Premiere serie : 

 Ammonites du Lusitanien de la Contree de Torres Vedras. 

 Direction des Travaus Geologiques du Portugal. Pp. 1-82, 

 pis. i.-xix. (Lisbonne, 1893.) 



THIS is the first part of M. Choffat's Monograph of the Ammonites 

 of the Jurassic rocks of the Torres Yedras region, under which 

 name the author includes the Jurassic rocks of the Montejunto 

 Chain, and those of the less elevated region, bounded on the east 

 by the Tertiary beds of the Tagus basin, and on the south by the 

 Cretaceous rocks extending from the Tagus to the Atlantic. The 

 author states that he has almost completed the stratigraphical 

 description of this region, but as this detailed account has not yet 

 been published, he prefaces his description of the Ammonite fauna 

 with a few remarks on the sequence of the beds. 



In the rocks which succeed the Callovian two great divisions can 

 be recognised — the Lower Malm, which the author calls "Lusitanien " ; 

 and the Upper Malm, comprising beds corresponding to the Port- 

 landian and Pterocerian of Central Europe, and strata containing 

 a fauna intermediate between that of the latter and that of the 

 Lower Malm. Cephalopods are exceedingly rare in the Upper 

 Malm, but the Lower Malm or Lusitanian has yielded the rich 

 Ammonite fauna described in the present work. 



The Lusitanian is divided into three principal divisions, which, in 

 descending order, are (i.) the Abadia series, having a thickness of 

 about 800 metres ; (ii.) the Montejunto limestones with a thickness 

 of from 200 to 500 metres ; and (iii.) the Gahaqo limestones with 

 a thickness of about 500 metres. 



The author then proceeds to a description of the species. The 

 CabaQo beds have furnished a few specimens of Cardioceras, which 

 cannot, however, be specifically identified. The genus Phylloceras 

 is represented by seven species, one being new, viz. Phylloceras 

 Douvillei, a species intermediate between Pliyll. subobtusitm, Kuder- 

 natsch, and Phyll. Beneckei, Zittel. Under Phyll. silenum, Fontannes, 

 the author makes some interesting observations on this and allied 

 species, and to this species he refers the form which Sharpe recorded 

 from this region as Ammonites tortisulcatus, d'Orbigny. One species 

 of Lytoceras, which the author compares with L. Adeloides (Kuder- 

 natsch), has been furnished by the Montejunto beds. Harpoceras is 

 represented by three species, one being new, but not named, whilst 

 Ochetoceras, which is regarded as a subgenus of Harpoceras, is 



