6 HENRY S. WASHINGTON 



of eruptions which formed a number of cones. The only clue to what 

 lies beneath these is given by a small fragment of a light-colored, 

 medium-grained, olivine-bearing, hornblende-diorite, which I found 

 imbedded in a piece of scoria at Monte Rosso, and which is evidently 

 a fragment of a plutonic rock from the basement brought up by the 

 lava stream. In this respect Linosa resembles Pantelleria, where 

 Foerstner^ reports fragments of hornblende-granite likewise imbedded 

 in the lava and tuffs, and which he refers to the basement complex 

 of the island. 



Small as is the island it yet shows nine distinct volcanic cones,^ or 

 centers of eruption, which may be referred to two distinct periods of 

 activity, distinguished by the materials which compose them. 



The first period is characterized by cones of basaltic tuff, lava being 

 represented in these only as included blocks. Not only do these tuff 

 cones show signs of greater age than the cinder cones in the greater 

 extent to which they have suffered by erosion, but in many cases the 

 tuffs are seen to be overlaid by the cinders and lavas of the cones of 

 the second period. 



In the center of the island is a rather prominent ridge of dark, 

 greenish-gray tuff, running north and south, to which the name of 

 Monte Bandiera is applied, and in the west slope of which the rude 

 chambers mentioned above have been hewn. This ridge is the west 

 wall of what is. apparently the oldest cone of Linosa, to the east of it 

 two distinct craters being visible. The most northerly of these, for 

 which I could learn no name, but which may be called the North 

 Bandiera Crater, is composed largely of yellow, with some dark- 

 gray tuffs, which contain angular blocks of compact basalt. This 

 crater, which measures some 300 meters across, is not very well 

 preserved, but shows a well-defined rim on the west and south, the 



1 H. Foerstner, Boll. Com. Geol. Ital., 1881, p. 550. 



2 Speciale considers that there are but five eruptive centers, namely: Monte 

 Ponente proper (with which he includes Monte Pozzolana), the cone which I have 

 named Monte Raneri, Monte Vulcano, Monte Rosso (of which he mentions only the 

 barranca on the north, not speaking of the summit crater), and Monte Bandiera 

 (which includes the two large craters immediately to the east, as well as Monte Bian- 

 carella to the north). He considers Monte Calcarella as forming a part of Monte 

 Vulcano and does not mention the well-defined cone of Monte Levante, nor does he 

 consider that the tuff and lava cones belong to two distinct periods. 



