274 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 13, 



robba on the south, M. de Zigno has fully developed the order and 

 component parts of the '* cretaceous system" of Northern Italy. 

 Identifymg the "biancone " with the '* majolica" of Milan, he shows, 

 by its several species of Crioceras and many species of Ammonites, 

 published by D'Orbigny as neocomian from Provence, that these 

 Italian limestones form truly the base of the cretaceous rocks, and are 

 perfectly to be distinguished from the grey and red scaglia above 

 them, and from the Oxfordian Jura or "ammonitico rosso" beneath 

 them. I can only venture to differ from the Italian geologists when 

 they state that a limestone between the neocomian and the upper 

 scaglia contains nummulites. All the small bodies supposed to be 

 nummulites'^ i when seen on the surface of such cretaceous lime- 

 stones, have proved to be other genera of foraminifera (chiefly Or- 

 bitolites) when closely examined. The course of sandstone intercalated 

 between the so-called neocomian and the scaglia or chalk is perfectly 

 in accordance with the section of the Griinten and Bavarian Alps (see 

 p. 204). 



In the Euganean hills, then, as in the Venetian Alps, the upper 

 member of the chalk is surmounted by the well-known lower tertiary 

 nummulitic rocks of the Yicentine, in which species of nummulites 

 occur, together with Turbinolia and other fossils. This tertiary 

 group runs into the hills south of Yicenza, which constitutes a part 

 of the eocene accumulations before alluded to. When, however, we 

 quit this Euganean outlier or island, and travel over the intervening 

 plains to the centre of the Apennines, we are, as in Liguria, immersed 

 in that very different mineral type to which allusion has already been 

 made. The limestones, some of which may stand in the place of 

 upper members of the cretaceous system, are traversed by serpen- 

 tines, and scarcely ever contain the trace of animal organic remains. 

 In vain, for example, does the geologist explore the limestones con- 

 stituting the chief ridge between Bologna and Florence, or the axis 

 between Liguria and Piedmont ; for with a few examples of fucoids 

 only, he can find no fossil base-line whatever in descending order, and 



* See " Sul Terreno Cretaceo dell' Italia Settentrionale," Padova 1846. When 

 the Men of Science were assembled at Venice in 1847, I in vain endeavoured to 

 detect a true nummulite found in tliis cretaceous rock. Among the unequivocal 

 neocomian fossil species of D'Orbigny, cited by De Zigno, are, Ammonites astie- 

 rianus, A. Guettardi, A. macilentus, A. Juilleti, A. inoRqualicostatus, A. Grasi- 

 anus, A. Morelianus, A. subfimbriatus, A. recticostatus, A. Matheronii, A. Ter- 

 verii, A. bidicJiotomus (Leym.), Belemnites dilatatus (Blainv.), B. latus (BL), 

 Crioceras Emerici (D'Orb.), C. Duvalii (Leveille), and C. Da Rio (Zigno). With 

 these and the Spatangus retusus are associated two species of Aptychus. One 

 of the latter has been supposed by Von Buch to occur also in the upper Jura. 

 In his memoir before referred to, M. Zeuschner cites two species of Jurassic Apty- 

 chi and the Terebratula diphya as being associated with many forms of neoco- 

 mian age in the same band of Carpathian rocks, an anomaly which I have endea- 

 voured to explain, pp. 260, 261. 



In his description, M. de Zigno further shows, that the conjoint elevation of the 

 cretaceous and overlying tertiaries has extended from the tract where I first de- 

 scribed it to the longitude of Feltre. Whilst these pages are passing through the 

 press, I learn from M. de Zigno that he has in great part carried out the work to 

 which I alluded p. 223. 



