610 J.Y.LEWIS OEIGIX OF PILLOW LAYJS 



Comparing with similar structures that have been interpreted as sub- 

 marine flows in Great Britain and elsewhere and considering the over- 

 lying Kurravaara conglomerate, "whose rounded and water-worn pebbles 

 show it to be a marine deposit." the author concludes that contact with 

 water has been the factor that favored the development of the pillows. 



ICELAXD AXD TEE FAROE ISLAXDS 



Johnston-La vis^' mentions having seen many beautiful examples of 

 pillow lavas in Iceland in which the lavas had the appearance of having 

 entered soft sediment on the sea-floor. Parts of Cape Eeyk janes, at the 

 southwestern extremity of the island, furnish good examples. Anderson^^ 

 refers to the lava stream that crossed Lake Myvatn. in northeastern Ice- 

 land, and extended some miles down the valley below the lake. A number 

 of spiracles were formed by the water and the mud : the larger ones built 

 cinder cones and the smaller ones, chiefly on the lava stream below the 

 lake, where the action was less violent, formed small cones made up of 

 lava masses comparable in size and shape to pillow lava. 



In 1880 James Geikie'^ attributed to weathering the numerous ex- 

 amples of spheroidal structure that he observed in the Faroe Islands. 

 Whereas in ordinary flow structure the amvgdules show a distribution in 

 parallel horizontal lines, "they also occasionally show a kind of curled, 

 coiled, or involved arrangement, as if the rock had been rolled over on 

 itself while in a plastic or viscous state." Archibald Geikie®*^ also speaks 

 of the tendency of the vesicular basalts of the east side of Sudero to 

 weather into globular forms resembling agglomerates. It seems highly 

 probable that some of these will prove on reexamination to be true pillow 

 or ellipsoidal basalts. 



EAST IXDIES 



Terbeek^^ has described a series of melaphyres of "'spilitic type" in the 

 Island of Ambon. Dutch East Indies. A bed with amygdules of calcite 

 and chalcedony is composed of irregular spheroids from the size of a man^s 

 head to a meter in diameter. The masses are broken by radial, calcite- 

 filled joints and coated with a black lustrous resinous tachylite. This 

 glass and its alteration products also fill the spaces between the spheroids. 

 The altered dull gray rock within consists of basic plag-ioclase in a brown 



5' H. J. .Joliuston-Lavis : The South Italian Volcanoes. Naples. 1891. p. 43 (foot- 

 note). 



58 T. Anderson : Quar. .Jour. Geol. Soc. London, vol. 64. 190S. p. 271. 



29 James Gelkie : On the geology of the Faroe Islands. Trans. Roy. Soc. Edinhurgh, 

 vol. XXX. 1883. pp. 217-2G9. 



60 Archibald Geikie : Ancient Volcanoes of Great Britain. London, 1897. pp. 258, 259. 



«i R. D. M. Verbeek : Description geologique de Tile d'Ambon. Jaarbock van het Mijn.- 

 Tvezen in Nederl. Oost-Ind., Batavia, vol. xxxiv, 1905. 



