Ch. x] and its fossils. 125 



Bones of vertebrated animals are rare in tlie loess, but those of the 

 mammoth, horse, and some other quadrupeds have been met with. At 

 the village of Binningen, and the hills called Bruder Holz, near Basle, I 

 found the vertebrae of fish, together with the usual shells. These ver- 

 tebrai, according to M. Agassiz, belong decidedly to the Shark family, 

 perhaps to the genus Lamna. In explanation of their occurrence among 

 land and freshwater shells, it may be stated that certain fish of this fam- 

 ily ascend the Senegal, Amazon, and other great rivers, to the distance 

 of several hundred miles from the ocean.* 



At Cannstadt, near Stuttgardt, in a valley also belonging to the hydro- 

 graphical basin of the Rhine, I have seen the loess pass downwards into 

 beds of calcareous tuff" and travertin. Several valleys in northern Ger- 

 many, as that of the Ilm at AVeimar, and that of the Tonna, north of 

 Gotha, exhibit similar" masses of modern limestone filled with recent 

 shells of the genera Planorhis^ Lymnea^ Paludina^ &c., from 50 to 80 

 feet thick, with a bed of loess much resembling that of the Rhine, occa- 

 sionally incumbent on them. In these modern limestones used for build- 

 ing, the bones of JElephas primigenius^ Rhinoceros tichorinus^ Ursus, 

 spelwus, Hymna spelcea, with the horse, ox, deer, and other quadrupeds, 

 occur; and in 1850 Mr. H. Credner and I obtained in a quarry at Ton- 

 na, at the depth of 1 5 feet, inclosed in the calcareous rock and surrounded 

 with dicotyledonous leaves and petrified leaves, four eggs of a snake of 

 the size of the largest European Coluber, which, with three others, were 

 lying in a series, or string. 



They are, I believe, the first reptilian remains which have been met 

 with in strata of this age. 



The agreement of the shells in these cases with recent European species 

 enables us to refer to a very modern period the filling up and re-excava- 

 tion of the valleys ; an operation which doubtless consumed a long period 

 of time, since which the mammiferous fauna has undergone a considerable 

 change. 



* Proceedings of Geol. Soc. ISo. 43, p. 222, 



