34 



Fossil Fishes. 



Table-case, 

 No. 49. 



Wall-case, 

 No. 15. 

 Table-cases, 

 Nos. 49 to 51. 



existing " Capelin " (Ifallotus villosus) is also found fossilized in 

 concretionary nodules in comparatively recent clays on the coast of 

 Greenland (Fig. 72), in Norway, and on the banks of the Ottawa 

 Kiver in Lower Canada. Of the latter curious fossils, several 

 examples are shown from these various localities. The shape of 

 the nodule in each case is observed to correspond precisely with 

 the contour of the enclosed fish, and the concretion is probably due 

 to the escape of gases from the decomposing body leading to a con- 

 centration of mineral matter at the spot from the clay around it. 

 As the Chipeidce, or Herrings (Fig. 73), which succeed in the 



Wall-case, 

 No. 15. 



Fig. 1Z,— Clupea brevissima (after Pictet and Humbert), Upper Cretaceous, Mount 



Lebanon. 



same table-case, have scarcely any notable point of difference from 



the Salmonidae, beyond the absence of the little adipose fin, which 



is situated upon the hinder portion of the back in the latter family, 



it is almost impossible, when dealing with fossils, to determine the 



limits of the two series. The adipose fin is most rarely preserved, 



and Agassiz therefore originally proposed to group these families 



together for palseontological purposes under the name of Halecidce. 



There are fine examples of Sardinius and Sardinioides from the 



Upper Chalk of Westphalia and Mount Lebanon occupying a thus 



doubtful position, and then follows an extensive collection of the 



extinct species of the true Herring ( Clupea). The earliest of the 



latter are met with in Upper Cretaceous strata, and the beautiful 



specimens from Mount Lebanon show the skeletal characters of the 



genus in a remarkably distinct manner ; observe, especially, the 



well-preserved series of large ridge-scales producing the sharp 



serrated edge of the abdomen. 



In the Syrian area, owing to some physical change in the con- 

 ditions of the sea at the time the Cretaceous deposits were being 

 laid down, these fishes appear to have been sometimes suddenly 

 destroyed in shoals, and buried at once by the fine calcareous mud. 

 This circumstance is well illustrated in the adjoining wall-case, by 

 several slabs of fossil limestone from Hakel, near 33eyrout, which 

 are covered with hundreds of their remains. Tertiary species of 

 Clupea are met with in the Eocenes of Monte Bolca, near Verona, 

 in the Canton Glaris, Switzerland, and in the Miocenes of Ulm, 



