428 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 22, 



Padua, from that coyeriug the oohtic plateau of the Sette Comuni, 

 and from that which forms the base of the subalpine hills of the Vi- 

 centin and extends to Friuli, the following fossils, which are highly 

 characteristic of the Neocomian formation : — 



Belemnites latus, Blainv. Ammonites Astiarianus, D'Orb. 



dilatatus, Blainv. • inasqualicostatus, If Orb. 



Ammonites incertus, D'Crh. infundibulum, D'Orb. 



difficilis, D'Orb. Grioceras Villiersianum, Leym. 



quadrisulcatus, B' Orb. Duvalii, Lev. 



Grasianus, D'Orb. Emerici, Lev. 



Morelianus, D'Orb. Ancyloceras pulcberrimum, D'Orb. 



ciyptoceras, D' Orb. Puzosianum, D'Orb. 



subfimbriatus, D' Orb. Aptychus Didayi, Coqd. 



rectirostratus, D'Orb. radians, Coqd. 



JuiUeti, D'Orb. 



In the upper beds I even found the Hippurites neocomiensis, D'Orb., 

 which seems to indicate the upper Xeocomian, or 'terrain Aptien.' 

 My observations, therefore, prove that the two Xeocomian groups are 

 found in the Venetian Alps and are represented by our biancone. 

 Palaeontology has also enabled me to discover traces of a formation 

 which Italian geologists have never yet recognized in our Alps ; I 

 mean the gault, or 'terrain Albien' of M. d'Orbigny. Indications 

 of this group are afforded by certain Cephalopoda found in a whitish 

 argillaceous limestone, lying on Xeocomian beds in the plateaux of 

 the mountains of the Sette Comuni. These consist of traces of a 

 Hamites, which I found near Galio, and which may probably be -the 

 H. Bouchardiarius, D'Orb., collected by MM. d'Orbigny and Bou- 

 chard de Chantereaux from the clays of the gault at Wissant ; a 

 young specimen oi Ammonites Velledi, Michelin, brought to me from 

 the environs of Canove ; another Ammonite which is unquestionably 

 the A. Royssiamis, D'Orb., from the valley of Freiizena ; and lastly, 

 the A. nodocostatus, D'Orb., originally found in the gault of Escar- 

 gnolle in the Tar by 3,1. Astier, and which was found here near Gaho. 

 Few as these fossils are, they authorize us to pronounce that the ar- 

 gillaceous limestone beds above the biancone in the Sette Comuni 

 contain gault remains, and are to be classed with that group. The 

 beds might easily be confounded with those above and below, for 

 in mineralogical characters they are not distinguishable. Organic 

 remains alone determme this horizon. 



Between the beds just described and the scagha, which I refer to the 

 chalk, or ' terrain Senouien,' occurs a limestone mass of variable thick- 

 ness, consisting of beds of very hard conglomerated rock, both the 

 pebbles and matrix of which are calcareous ; it contains also little frag- 

 ments of a sparry structure, which may be broken shell, and which give 

 the rock in some parts a crystalline aspect. This rock is most developed 

 in the neighbourhood of Belluno. ]\IM. Catullo and Pasini have 

 noticed it in the mountains which surround the lake of S. Croce and 

 form the heights of Alpago. The former gentleman refers it to the 

 Xeocomian period, and the latter gives it a still greater antiquity. For 

 my own part I place it in the upper greensand, or ' terrain Turonien,' 

 both from its geognostic position and from its organic remains. 



