chap. xv. Valley of Copiapo. 551 



Turritella Andii, d'Orbig. ' Voyage, Part. Pal.' 

 Pecten Dufreynoyi, do. 

 Terebratula ignaciana, do. 



The relations of these species have been given under the head of 

 Coquinibo. 



Terebratula aenigma, d'Orbig. t Voyage, Part. Pal.' 

 (var. E. Forbes, PI. V. figs. 13, 14). 



This shell M. d'Orbigny does not consider identical with his T. 

 senigma, but near to T. obsoleta. Professor Forbes thinks that it is 

 certainly a variety of T. aenigma, and his observations on this species 

 are given in the list of fossils from Coquimbo : we shall meet with 

 this variety again at Copiapo. 



Spirifer Chilensis, E. Forbes, PL V. figs. 15, 16. 



Professor Forbes remarks that this fossil resembles several car- 

 boniferous limestone Spirifers ; and that it is also related to some 

 liassic species, as S. Wolcotii. 



If these shells had been examined independently of 

 the other collections, they would probably have been 

 considered, from the characters of the two Terebratulae 

 and from the Spirifer, as oolitic ; but considering that 

 the three first species, and according to Professor Forbes, 

 the four first, are identical with those from Coquimbo, 

 the two formations no doubt are the same, aud may, 

 as I have said, be provisionally called cretaceo-oolitic. 



Valley of Gojpiajpo. — The journey from Guasco to 

 Copiapo, owing to the utterly desert nature of the 

 country, was necessarily so hurried, that I do not con- 

 sider my notes worth giving. In the valley of Copiapo 

 some of the sections are very interesting. From the 

 sea to the town of Copiapo, a distance estimated at 

 thirty miles, the mountains are composed of greenstone, 

 granite, andesite, and blackish porphyry, together with 

 some dusky-green feldspathic rocks, which I believe to 

 be altered clay-slate : these mountains are crossed by 



