cnAP. xn. Cone hiding Remarks on. 407 



the identity of mineralogical composition, from the 

 presence of fragments of lignite and of silicified wood, 

 and from the intercalated layers of imperfect coal, I 

 must believe that the coast-formations from central 

 Chiloe to Concepcion, a distance of 400 miles, are of 

 the same age : from nearly similar reasons, I suspect 

 that the beds of Mocha, Huafo, and Ypun, belong also 

 to the same period. The commonest shell in Mocha 

 and Huafo is the same species of Turritella ; and I 

 believe the same Cytheraaa is found on the islands of 

 Huafo, Chiloe, and Ypun ; but with these trifling ex- 

 ceptions, the few organic remains found at these places 

 are distinct. The numerous shells from Navidad, with 

 the exception of two, namely, the Sigaretus and Tur- 

 ritella found at Ypun, are likewise distinct from those 

 found in any other part of this coast. Coquimbo has 

 Cardium auca in common with Concepcion, and Fusus 

 Cleryanus with Huafo ; I may add, that Coquimbo has 

 Venus y)eiitianob, and a gigantic oyster (said by 

 M. d'Orbigny also to be found a little south of Concep- 

 cion) in common with Payta, though this latter place 

 is situated twenty-two degrees northward of lat. 27°, to 

 which point the Coquimbo formation extends. 



From these facts, and from the generic resemblance 

 of the fossils from the different localities, I cannot avoid 

 the suspicion that they all belong to nearly the same 

 epoch, which epoch, as we shall immediately see, must 

 be a- very ancient tertiary one. But as the Baculite, 

 especially considering its apparent identity with the 

 Cretaceous Pondicherry species, and the presence of an 

 Ammonite, and the resemblance of the Nautilus to two 

 upper greensand species^ together afford very strong 

 evidence that the formation at Concepcion is a Secondary 

 one ; I will, in my remarks on the fossils from the other 

 localities, put on one side those from Concepcion and 



