change). The coastline is irregular, with major indentations such as South Bay, False Bay, Moon Bay, Hero, Barclay, New Plymouth, Osogovo and Walker, and peninsulas such as Hurd ( long), Rozhen (), Burgas (), Varna (), Ioannes Paulus II () and Byers (). There are many islets and rocks lying in the surrounding waters, particularly off the north coast. More sizable among the adjacent minor islands are Rugged Island off Byers Peninsula, Half Moon Island in Moon Bay, Desolation Island in Hero Bay, and Zed Islands off Williams Point. Ice cliffs, often withdrawing during recent decades to uncover new coves, beaches, spits, points and minor islands, form most of the coastline. Except for the ice-free Byers Peninsula and some isolated patches, the land surface is covered by an ice cap with ice domes and plateaus in the central and western areas, and a number of valley glaciers formed by the more mountainous relief of eastern Livingston. Certain areas of the ice cap, especially near glacier termini or over steeper slopes, are densely crevassed and almost inaccessible without specialized equipment. Elsewhere, the surface is smooth, hard and comfortable for walking, skiing or snowmobiling. However, the danger of falling into some hidden crevasse masked by a snow bridge is ever-present, including in frequently visited and supposedly well-known localities. Protracted periods of warmer weather tend to make the snow bridges more unstable and hazardous. Typical of the island's glaciology are the conspicuous ash layers originating from volcanic activity on neighbouring Deception Island. The island hosts also several rock glaciers consisting of rock debris frozen in ice, such as those at Nusha Hill, MacKay Peak and Renier Point. Along with the extensive Byers Peninsula () forming the west extremity of Livingston, the ice-free part of the island includes some minor coastal areas at Cape Shirreff, Siddins Point, Hannah Point, Williams Point, Hurd Peninsula and Rozhen Peninsula, as well as slopes in the mountain ranges, and ridges and heights in eastern Livingston that are too precipitous to keep snow. Numerous meltwater streams flow in the ice-free areas during summer, extending from hundreds of meters up to 4.5 km. Byers Peninsula alone has more than 60 such streams and as many lakes, notably Midge Lake (587 by 112 m, or 642 by 122 yd), Limnopolar Lake and Basalt Lake. Several such streams, lakes and ponds are situated in the vicinity of the Bulgarian and Spanish bases