A Swiss geologist has called Masira Island paradis d'un petrographe. It is part of the territories of the Su tan of Muscat Oman, lying som 150 miles south of Ra's al Hadd, the cape at the extreme eastern corner of the Arabian peninsula. It is 40 miles long and 10 miles broad, being divided from the mainland by a channel 12 miles wide. At the northern end of the island there is a haven from the monsoon, and to the south a 7-fathom deep passage runs in from the Indian Ocean and con? tinues close to the inner shore of the island for about half its length. Geologically the island is almost entirely of igneous rocks, assigned by the late Dr. Lees to the Semail series. Basalt, serpentine, diorite and gabbro are all seen on the island. Overlying this series is the sedimentary Eocene, confined, with a few small exceptions lower down, to three flat-topped summits. Their shape and light colour make a striking contrast to all the other and numerous dark peaks of the range running along the length of the island. Seen from a flank, Masira could be described as resembling a half-submerged dragon, the notched hills along its length being the comb on the creature's back, the smooth plain at the northern end representing its neck and the reef off the northern point the dome of a submerged head. The central axis of the range is, however, broken by a gap at the centre of the island allowing easy access from coast to coast. The maximum height of the range, at the shoulders of the dragon as it were, is attained at Jabal Madrub, a conical hill 620 feet high. The climate is exceptionally agreeable. The hottest month is May, when the average maximum is 960 F, humidity 77 per cent. and minimum temperature 770. After May the effect of the monsoon begins to be felt, and the temperature falls. The coldest month is January, when the average maximum is 780 and the minimum 66?, with humidity at 64 per cent. In August, the average maximum temperature is 86?, the minimum 720 and humidity 74 per cent. with winds S. to SW. at between 10 to 15 knots. The prevailing wind is S. to SW. throughout the year except between November to March when it is usually from SE. or NE. at 10 to 15 knots during the day and 5 to 15 knots at night. In April the wind begins to veer once more to S. and SW. usually at 5 to 10 knots and gradually strengthens until it reaches 20 to 30 knots in July. The visibility is hardly ever known to be low enough to make a landing from the air dangerous, though sandstorms do occur sometimes between July and September. When the wind is strong from the south-west, thick spume covers the southernmost extremity of the island. Vegetation is scarce, though drinkable water is found frequently at between 6 and 12 feet near the shore. A few springs of water in the centre of the island support straggling date-palms in gullies draining eastwards. The direction of the two largest watercourses in eastern Arabia, which come from the Eastern Hajar range (9000 feet) is towards Masira Island, and though both of them disappear before reaching the coast of the mainland it is possible they continue subterraneously. More wells than those now worked on Masira were once in use and more palms cultivated than at present. The inhabitants today live in villages and hamlets on the coast, in small huts made of palm-fronds, their livelihood being gained from the sea, with dried fish as the chief export. The place names shown on the map accompanying this note have been checked locally and are now believed to be as accurate as they can be. The language is Arabic and a short list of unusual topographical terms is given on page 502. A count of the huts on the island, allowing five persons to each hut, gives a total of just under two thousand inhabitants. At certain times of the year some of the men are away at sea, going with small sailing vessels as far as Zanzibar and Mombasa, or