278 E. 0. Homy—Neio Cone of Mont Fell 



lip from below, and masses which have fallen or been blown 

 off from the latter. The spine or tooth consists of " solid " rock 

 which seems to have been pushed up bodily into its present po- 

 sition, and to be maintained there, somewliat like the stopper 

 in a bottle, by friction against the sides of the neck and by the 

 expansive forces underneath. The shape of the spine, with its 

 sides forming angles of 75°, 87° and even 90° with the horizon- 

 tal, is a strong argument against the theory that it has been 

 formed by ejected blocks or bombs which were sufficiently 

 pasty to stick together on falling, and in favor of the " stop- 

 per " theory. Furthermore, the northeast side of the spine 

 presents a fairly smooth, vertically grooved surface, as if it 

 had been slickensided by friction against the side of the con- 

 duit during its ascent (see figs. 5, 6 and 7, PL XII, XIII). The 

 great and sudden changes in the altitude of the spine with 

 reference to the rest of the cone point in the same direction. 



Great ribs or dikes ot* lava extend to the sides of the new 

 cone from the base of the spine on the northeast, southeast, 

 south and west. Those of the southern and southeastern por- 

 tions of the cone appear in iig. 4, PI. XII. The lofty tooth or 

 spine is rifted and iissured in every direction, and portions of 

 it are constantly falling from its sides. Some of the vertical 

 fissures are very prominent on the east side and evidently 

 connect with fluid lava beneath, for they have been observed" 

 to become luminous at night from below upward, and the light 

 has died out gradually from above downward. The author 

 was not fortunate enough to witness this phenomenon, which 

 substantiates the cumulo-volcano theory so well ; he only saw 

 the cone luminous at the base of the spine on the southwest 

 side, which is the source from w^hich have originated most of 

 the recent heavy dust-flows and minor eruptions. 



The northeast side of the spine is strikingly different in 

 appearance from the southwest side thereof. The former shows 

 a nearly smooth surface which is almost polished in its effect. 

 In the light of the rising sun the spine looks like an enormous" 

 white monument rising above the mountain. The true color 

 of the northeast side of tlie spine, however, is more a reddish 

 brown with a whitish incrustation over a part of it. The south- 

 west side of the spine constantly shows fresh surfaces on account 

 of the portions falling off, and this side is gray or reddish gray 

 in color. 



]^o one can say yet exactly what the nature of the spine is, 

 but the probabilities are that it is largely pumiceous in tex- 

 ture, judging from its being so rifted, from the readiness v/ith 

 which the masses break off from it and especially from the 

 abundance of pumice in the new material filling the gorge of 



* Lacroix, Comptes Rendiis, Dec. 1, 1902. Author's separate p. 5. 



