of Mount Lebanon. 241 



2. The existence of a certain number of genera or groups, 

 which, as far as we know at present, characterize the Cretaceous 

 epoch. Such are the genera Scombroclupea and Lepiosomus, the 

 groups of Dercetis and EuryphoUs. 



3. The great number of extinct genera which contribute to 

 give these faunas a special physiognomy. These are, at Hakel, 

 Pseudoberyx, Petalopteryx, CoccoduSf Aspidopleurus, and Cyclo- 

 batis; and at Sahel Alma, Pycnosterinx, Cheirothrix, Rhinellus, 

 and Spaniodon. 



4. The fact that among the genera which are still represented 

 by living species, those which are the most abundant at the Le- 

 banon are precisely such as belong also to the Cretaceous epoch. 

 We may mention in particular the type Beryx, which is pre- 

 eminently Cretaceous, although represented at the present day 

 by some species in the warmer seas. We may also cite the 

 Clupea, the existence of which is demonstrated as far back as the 

 Cretaceous period, and the Chirocentrites, the maximum develop- 

 ment of which is equally characteristic of that epoch. 



The fish which are not referable to one or other of these cate- 

 gories are very few in number, and occupy but a subordinate 

 position in the Lebanon faunas. 



But, although we are tolerably certain of the general fact that 

 these faunas are Cretaceous, we find it a much more embarrass- 

 ing matter to decide to which of the subdivisions of this long 

 age they should properly be referred. The history of fossil fish 

 presents still too many breaks to admit of our applying here the 

 same methods as hold good in the case of MoUusks and Echi- 

 noderms, and we are forced to content ourselves with a certain 

 degree of probability. 



The first point to determine is that no species of Mount Li- 

 banus has ever yet been found in any other deposit, save certain 

 parts of Syria and Asia Minor which belong to the same epoch, 

 and of which we have already spoken. Consequently our com- 

 parisons become limited to the more uncertain relations between 

 genera and natural groups. 



We have compared the faunas of Lebanon with that of Voi- 

 rons (as made known by one of the authors*), with that of Co- 

 men in Istria (as studied by MM. Heckel, Kner, and Stein- 

 dachner), with that of the Chalk of England, and finally with 

 that of the Chalk of Westphalia (the numerous species of which 

 have been described in an important memoir by M. von der 

 Marck). 



Making allowances for insuflBcient data, we give the following 

 as the results of these comparisons : — 



* F. J. Pictet, * Paleontologie suisse,' 1868, 1" serie. Descriptiou des 

 fossiles du terrain neocoinien iles Voirons. 



Arm, ^ Mag. N. Hist. Ser. 3. Vol. xs'xn. 17 



