ADDITIONAL COMMENTS ON THE GEOLOGY OF THE JUAN FERNANDEZ ISLANDS 69 



Fig. 28. High-temperature exsolution of spinel, enclosed in olivine phenocryst (PI. I, Fig. 2). Light 

 lamellae, according to Ramdohr probably magnetite in groundmass of excess spinel, x 600. 



Photo P. Ramdohr. 



Fig. 29. Magnetite in groundmass of the lava bed as seen in PI. I, Fig. i pa:t-a!iy c!):inge(l to 

 hematite (martite). x 300. Photo P. Ramdohr, 



5 — 516795 The Nat. Hist, of Juan Fernandez and Easter Isl. Vol. I. 



