218 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 19, 



of Sautorin, deep as it is, is still shallower than some of the adjoin- 

 ing parts of the ^lediterranean, and might, if upraised, present a dry 

 crater connecting by a chasm with the sea. 



The greatest depth of the crater or gulf according to the late sur- 

 vey was found to be between the shores that are highest ; that is to 

 say, between that part of Thera where Merivali is situated and the 

 opposite cliffs of Therasia, which are about four miles distant. Here 

 the somidings reached 213 fathoms. The height of the escarpment 

 at Meriyah is 11/1 feet, that of the high land in Therasia 936 feet, 

 the cliffs on both sides above water and below being very steep and 

 in great part perpendicular. If therefore, says Lieut. Leycester, the 

 crater were empty, the observer looking down into it from Merivali 

 would behold a frightful abyss 2449 feet in depth, the bottom con- 

 sisting generally of reddish or brownish clay, and the opposite side, 

 or that of Therasia, would be only 235 feet less deep. A vast circu- 

 lar cavity, nowhere less than 1200 feet deep, would be seen to be 

 eighteen miles in circumference, the encircling cliifs broken in one 

 place, and one only, by a ra^dne 11/0 feet deep. The walls of the 

 great crater would be nearly twice as high on the north-east as on the 

 south-west side, on the whole very uniform in outline ; but at Scau- 

 rus a narrow promontory would jut out from the steep chfp, about 

 one-third of a mile mto the gulf. 



In the middle of this great caldera (the waters being drawn off) a 

 single volcanic mountain would appear, bearing the same relation to 

 the surrounding deep sea and circular escarpment which the Peak of 

 Teneriffe bears to its moat and bastion, as described by Yon Buch, or 

 which the active volcano in the centre of Barren Island bears to the 

 marine channel and outer girdle of rocks by which it is surrounded. 

 This central mountain (see sections figs. 5 & 6, p. 216) is about five 

 miles and a half in circumference at its base, and is surrounded on all 

 sides by deep water. Its longest diameter is about two miles, in a 

 direction from north-east to south-west. It has five summits, which 

 spring from a ridge at the height of about 1000 feet from the bottom 

 of the crater. Three of these summits, called the Kaimenis, rear their 

 heads above the present level of the waters. The north-eastern, called 

 the Little Kaimeni, or little burnt island, is 222 feet above water, formed 

 by eruption in 1/53. There is a cone on it having a crater eighty feet 

 deep, and on the north side of it a considerable bank, of large blocks of 

 lava and ashes. The top of this cone is 1 550 feet above the base of the 

 mountain. The middle, or New Kaimeni, was produced during erup- 

 tions in 1707 and 1 709. It was composed at first of two parts, which 

 were afteiT^'ards united. Its summit consists of a cone, which rises 35 1 

 feet above water. Its sides slope at an angle of 33°, and its shape, 

 well delineated by Boiy St. Yinceut in plate 37. fig. 2 of the Morea 

 Expedition, is precisely that of cones of single eruption in Auvergne, 

 or on the flanks of Etna. The crater on the summit is eighty yards 

 in diameter, according to Lieut. Leycester, and the highest point of the 

 cone is 1629 feet above the bottom of the abyss. The south-western 

 island, or the Old Kaimeni, is 328 feet above water, or twenty-three 

 feet lower than the highest of the other peaks. The channel which 



