ing to within half a mile at the sea. The hills around ranged from 500 ft. to 1,245 ft., and we considered everything inside this barrier as being quite safe. Just about the time, or shortly before, the last stream reached the sea we saw a dense volume of black smoke rising from the hilltop on the east side, near the entrance to the valley and overlooking the hospital. When day broke we discovered the top of the hill was being blown out, but as yet there was no appearance of fire; only some continuous expulsive force was driving the hilltop out. There were no separate explosions observable. The force was continuous. Soon, however, fire appeared, and the force increased quickly, so that one could observe the hill steadily diminishing in height. The side of the hill looking west was acted upon, and decreased more quickly than the other sides, and about 10 a.m. on the 7th lava began to flow down the hillside into the valley and through part of the hospital compound. (e.) The ground in the valley could be felt in motion—a kind of heave—not violently, but reminding one of a slight motion at sea. This motion was not continuous, but at very short intervals. Shortly after 10 a.m. an explosive eruption blew the hospital and other buildings into the air. The force of this explosion was terrific. First a great sheet of what appeared to be electric flame flashed from the ground, and immediately following was a mighty roar and crash like myriad thunder-claps one piled on another. The heat, too, was intense. We could see for an instant only the corrugated iron spreading out like scintillating glass, and then it was gone. Explosion then followed explosion almost continuously for four days at least. Sometimes there would be a short interval, but the intervals did not last long. (f.) We discovered at daylight that another lava-stream had flowed behind our hills towards Craig's Cove. This stream stopped on the plain about 500 yards from the beach. This stream was the biggest of all, being in some parts about three-quarters of a mile wide. (g.) About 3 p.m. on the 7th a submarine volcano broke out about a mile from the shore off Lamb Point. Soon an island was formed, and within sixteen hours had joined the mainland. After four days the activity of this volcano ceased. On Tuesday, the 9th December, a geyser suddenly broke out a few hundred yards inland from Craig Point. Water must have been forced to a considerable height, for we were drenched in a mud bath while over 500 yards from the shore. The geyser lasted for probably fifteen minutes or more. Immediately after the geyser ceased a roar like a rushing torrent was heard. Very soon a river extending in width from the trading-station at Craig Point to Malver tore its mad rush to the sea For half an hour or so there was a great volume of water, which gradually diminished in volume, and apparently in speed. This river ran for at least six hours. On Sunday, the 7th December, there were six distinct craters in the vicinity of Dip Point, West Ambrym. The whole district was undoubtedly a fairly recent volcanic area. In the valley behind the hospital, as well as at Craig's Cove, outcrops of lava could be seen at various points, and there was little evidence of weathering, the lava in many places appearing rugged, as it does soon after cooling. Petrography. The rocks of Ambrym do not appear to have been described hitherto, and it has therefore been thought advisable to add to this account of the eruption by Dr. Bowie a few notes on the rock-specimens that have been