232 Washington — Catalan Volcanoes and their Rocks. 



and especially the great preponderance of ferrous over ferric 

 oxide, as well as the comparatively large amount of Ti0 2 , are 

 the chief features to be noted. 



Classification. — The norm of this rock is as follows : 



Or... 



S-90 



Ab .. 



24-63 



An .. 



. 19-18 



Ne... 



. 2-56 



Di... 



. 19-59 



01... 



. 12-88 



Mt .. 



4-18 



11 ... 



7-30 



Ap.. 



1-00 





100-22 



Rest 



•37 



) _Sal_ Class III 



V 52-71 1 Fem - r23 Salfemane 

 ) \ 55-27 



2 ' 56 ^ F =20-59 0rder 5 



- 32-47 ^ -k Gallare 



1-11-48 1- 44-06 K - + Na -° = 1-04 R ^ 3 



1-00 J 



CaO' Camptonase 



K 2 Subrang 4 



Na 2 " Camptonose 



100-59 



The relations of norm and mode are clear on comparison of 

 the figures above with the mode given on a previous page. 

 The modal augite takes up all the normative diopside, with a 

 little of the normative anorthite, olivine, and magnetite, but 

 the divergence of the mode from the norm is not a serious one. 

 As the soda-lime feldspar was determined optically as a labra- 

 dorite of about the composition Ab^Ai^, there must be present 

 about 15 per cent of a soda-orthoclase, of about the composition 

 Or 3 Ab 2 , and this, with 3 or 4 per cent of nephelite, is to be 

 looked for in the colorless, doubly-refracting base. On the 

 whole therefore the mode may be considered to be a normative 

 one, and the rock may be briefly described as a femphyro- 

 interserti-camptonose. In the current classifications it is a 

 feldspar-basalt, texturally of the common intersertal type. 



Occurrence. — This type of camptonose was observed by me 

 only in the district around Olot, where it forms extensive 

 flows with well-developed prismatic structure. Some prom- 

 inent localities where this type was collected are : the upper 

 flow at Castellfullit,* a flow of Puig Estany near the 45 

 kilometer stone on the road from Olot to Castellf nllit, a flow 

 from the Puig Dolors in the Torrent Mai near Castellf ullit,- 

 and the flow in the valley of the Rio Ridaura north of La 

 Garrinada and also near San Juan las Fonts. A slightly 

 weathered lava, mottled in light and dark gray, which was 

 met with as blocks on the south slope of La Garrinada, near 

 the lowest crater, as well as at Castellfullit, also apparently 

 belongs to this type. 



*My specimens of the lower flow were unfortunately mislaid, but in the 

 field no difference eon Id be detected between these and those of the upper 

 flow. 



