C. SKOTTSBERG 



Table XIV. Analyses of rocks and soils. 



II. Olivine basalt, Masatierra, Bahia Cumberland. 

 VI. Picrite basalt, Masafuera, dike rock. 

 VII. Iddingsite basalt, Masafuera, 1000 m. 



1. Masatierra, Portezuelo de Villagra, c. 575 m. Dark brown humus soil, a mixture of finer ma- 

 terial and grains of varying size, kept together by a felt of roots. 



2. Masatierra, near Portezuelo, c. 550 m. Almost black, gravelly humus soil, covered with filmy 

 ferns. 



3. Masafuera, dark brown forest soil, weathered basalt fragments and humus particles mixed. 



4. Masafuera, lower slopes of Cordon del Barril. Dry grass-land. Yellowish-reddish sand with rock 

 fragments. 



landern an das Gebiet der Roterde an, aber, soweit dies Ramann feststellen konnte, 

 immer in den feuchteren Lagen" (p. 183). The Mediterranean red soils (Terra 

 rossa) are exclusively found on limestone or rocks rich in lime (p. 195). Yellow 

 soils in the sense of Blanck have been described from South France, northern 

 Italy, Morocco, Japan, etc., everywhere within a region of a less extreme winter-rain 

 climate. They were stated to occur on various kinds of rock, as gneiss, basalt, 

 tuff and limestone. Very likely the soils of Juan Fernandez, the Alpine soils per- 

 haps excepted, belong to this type. 



According to the survey undertaken by Ouensel the predominating rocks of 

 Masatierra are olivine basalts, differing only in their content of olivine; "in general 

 one may say that types with a very high content of olivine are restricted to lower 

 elevations, whereas higher up more normal olivine basalts predominate" (1. c. 45). 

 With regard to the texture, coarse-grained lava beds, "doleritic basalts", seem to 

 occupy lower horizons up to about 200 m. "At higher levels the basalts have a 

 more normal character . . . most of these lavas are vesicular, scoriaceous or slaggy" 

 (1. c. 49). These lavas as well as the feldspar basalts of Masatierra, which form 

 an intermediate horizon between 400 and 500 m — the locality illustrated on 

 fig. 9, where the "columnar structure of feldspar basalt" is shown, is, however, 

 situated at about 600 m above sea-level — are very hard and apparently more 

 resistant to weathering processes than the doleritic lavas of the lower levels, where 

 also agglomerate beds and tuffs occur, easily eroded by running water and broken 

 down by abrasion along the the coast. 



