TKRTIARY FLORA OF CHILE; 79 



These are the divisions quoted by Russel in his account 

 of the Coal fields of Chile (op. cit.). As Briiggen points out 

 these divisions have little if any basis in fact. Machado 8 in 

 1912 adopts much the same divisions which he calls the Quir- 

 iquiniano, Lautariano (Lota, Coronel) and Lebusiano 

 (Arauco) stages. 



The oldest known rocks in the region are highly meta- 

 morphosed sedimentaries now altered to mica schists, seri- 

 cite and biotite gneiss, phyllites, grauwackes, etc. These are 

 of the greatest interest since at various places in the Bio Bio 

 valley they contain black schists, arkosic quartzites and an- 

 thracitic streaks, of considerable thickness. Between Talca- 

 mavida, Gomero and Buenoraqui these contain fossil plants. 

 From this region Briiggen has recorded 9 Cladophlebis, 

 Tceniopteris, Sctgcnopteris, Zamites, William sonia, Gink go 

 and Eqnisetites. These determinations are sufficiently reli- 

 able to prove that their age is either Jurassic or Lower Cre- 

 taceous and this raises the question if the similar metamor- 

 phic rocks of the Coast Range in other regions may not be as 

 young as Jurassic or Lower Cretaceous instead of being very 

 old, as they have frequently been considered. 



The intrusive rocks are andesitic and granodiorites, and 

 they are, in part at least, more recent. Following these older 

 Mesozoic rocks after a considerable interval of time had 

 elapsed, possibly representing the whole of the Lower Cre- 

 taceous and the earlier part of the Upper Cretaceous, are a 

 series of conglomerates and highly fossiliferous sandstones of 

 Senonian age. The most recent studies of this fauna, which 

 has been found on Quinquina Island, at San Vicente, Lir- 

 quen and Colico, are by Steinmann 10 and Wilckens. 11 Briig- 



8 Machado, M. R., El carbon de Chile i su distribucion jeografica. 

 Bol. del Mnseo Nacional de Chile IV, 1912. 



9 Briiggen, J., Bol. Soc. Nacional de Mineria, 3d ser. vol. 25, pp. 19- 

 20, 1913. 



10 Steinmann, G., Neues Jahrb. Beil. Bd. 10, pp. 1-106, 1895. 

 "Wilckens, O., Idem., Beil. Bd. 18, pp. 181-284, 1904. 



