THE
ERUPTION
OF
21
PELÉE
Lacroix has urged, seems undeniable; indeed, the question of differences would seem to resolve itself, so far as a direct comparison is made possible, almost entirely into one of not very important details. The greater or lesser activities of the two volcanoes m a y account fully for these differences. I n m y work " T h e Tower of Pelée" (p. 32) I have remarked: " U n t i l the activity of Pelée will have so far lessened as to permit of a closer study of the dome its full nature cannot be determined, perhaps not even to the extent of allowing us to say in how far, if a t all, it is related to the hollow, oven-like forms which Dana and others have described from the Hawaiian Islands under the name of " d r i b l e t " cones, and of which Israel C. Russell has more recently given us exaggerated types from among the J o r d a n Craters of Oregon. One of these " o v e n s " measures 20 feet in height and 40-50 feet in basal diameter.* T h a t the intumescing Pelée dome is a t times largely hollow seems sufficiently established b y the markedly diminished height which follows or accompanies eruptions of only moderate intensity. I n m a n y cases of such eruption there would appear to be a general c o l l a p s e . " †Unfortunately, a t this later day (1907) the dome is so completely buried beneath the debris from the fallen obelisk t h a t its accessibility for study is, if anything, less t h a n it was before. The actual summit, which bears the craggy serrations of the base of the obelisk, was still unattainable a t the time of m y visit in Feb., 1906. However closely we m a y approximate the structure of the Pelée dome to other domes, the problem of the obelisk remains a p a r t b y itself. The geol ogist, failing to note any similar structure among recent volcanoes, is tempted to make comparisons with those giant stocks of lava which have long been recognized as " volcanic n e c k s " and "laccolitic cores," and which are presumed to owe their prominent forms in the landscape to differential erosion of the land-surface. T h a t some or m a n y of these cores are only such resisting blocks overlooking an eroded land-surface cannot be questioned, b u t it is not so cer tain t h a t all are of this nature, and some m a y well be of the type of structure which Pelée has presented in its extraordinary obelisk. One cannot resist the conclusion, even without the direct support of facts, t h a t there m u s t have been other protrusions before the one of 1902, and some of these ought to be pre served somewhere; b u t where? Sir Richard S t r a c h e y ‡calls attention to " p l u g s " of trap, said not to be uncommon, rising out of the Dekkan plateau, which he believes to be the analogues of the Pelée core. A sketch of one of these, made as early as 1839, is in its form certainly very suggestive. Another structure might, perhaps, also * " G e o l . S o u t h w e s t e r n I d a h o a n d S o u t h e a s t e r n O r e g o n , " Bull.
U. S. Geol. Survey,
1902,
No. 217, p. 52. †Professor Russell, in t h e r e p o r t referred to, presents a n exceedingly suggestive illustra tion of a (pressure) " d o m e in recent l a v a , " also a m o n g t h e J o r d a n lavas of Oregon; b u t it is held t h a t t h e l a v a of t h i s a n d similar domes was a n t e c e d e n t l y horizontal, a n d was forced u p as t h e result of l a t e r p r e s s u r e (p. 54, pl. xv., Fig. A). ‡Nature, October 15, 1903, p. 574.