32 A NATURALIST ON THE "CHALLENGER." 



accustomed to volcanic shores, being composed of fine volcanic 

 sand which is absolutely black. The sand is made up of ground- 

 up lava and ejected dust, and is full of crystals of olivine, 

 augite, hornblende, and quartz, with abundance of magnetic iron 

 particles, which cling to a magnet when it is brought near. 



The ship was off Pico in the evening of July 2nd. The 

 clouds gradually cleared off the island, at first hovering about 

 its summit, then remaining as a belt some way below the top 

 of the cone, and finally disappearing altogether, and leaving the 

 majestic peak in full view, lit up by a splendid red sunset glow. 

 The peak is a steep cone, rising abruptly to 7,613 feet above sea 

 level from a more gently sloping base, on which are numerous 

 secondary craters which look like little pimples on the surface of 

 their huge parent. The top of the cone is cut off horizontally and 

 out of the huge crater on the top arises towards one side of it a 

 little secondary cone which forms the highest point of the whole. 



St. Michael's Island, July 4th to July 9th, 1813. — We neared 



the island of San Miguel. The island has mountains of from 

 2,300 to 3,500 feet altitude at either end, and a lower range of 

 hills joins these together. Ponta Delgada, the capital of San 

 Miguel, lies on the sea shore opposite, about the middle of the 

 lower ransje of land. 



The volcanic cones and slopes leading from these to the sea 

 are formed of light pumice and ash soil, very friable and easily 

 cut into by the action of water. Hence, water-courses have cut 

 their way deep into the surface of the country, and as San 

 Miguel is viewed from seawards, its most striking feature is 

 formed by the numerous deep gullies which are seen running 

 parallel to one another, and with almost straight courses from 

 the high land down to the sea. Ponta Delgada is composed of 

 houses similar to those of Fayal, but it is not nearly so pretty as 

 the latter town, the land behind not being steep, and there being 

 no bay shut in by hills. A breakwater is required to form a 

 harbour. 



I formed one of a large party which paid a visit to the valley 

 of Furnas and its hot springs, distant about 30 miles from the 

 port town. We travelled in carriages, each drawn by four 

 mules. From the nature of the country already described, 



