Central Pirin extends between the Todorova Polyana Saddle and the Popovi Livadi Saddle. It constitutes the smallest and the shortest of the three subdivisions, covering only 7% of Pirin's total area. It is composed of crystalline schists and granite, as well as of marbled limestone in the south. Because of the karstic relief there are no lakes; the rivers springing up from Central Pirin are short and with low water volume. It is largely covered by deciduous forests. The highest peak is Orelyak (2,099 m), while the other summits are under 2,000 m. South Pirin stretches from the Popovi Livadi Saddle to the Paril Saddle and is the lowest and least rugged part. The highest peak is Ushite at 1,978 m, although Sveshtnik (1,975 m) had long been considered the highest summit. It constitutes 19% of the mountain's territory. Despite being characterised with relatively flat ridges, its lateral slopes are steep. South Pirin is composed of granite with marbled limestone in the periphery. It lacks glacial forms and is covered with forests. Like Central Pirin the springs are short and with low water discharge. Geology, relief and peaks in Pirin Geologically Pirin is a horst forming a massive anticline situated between the complex graben valleys of the Struma and the Mesta, formed by metamorphic rocks — gneiss, biotite and crystalline schists, amphibolite, quartzite and marble. Granite rocks cover 62% of the mountain's area. The tectonics of the Pirin is primarily the result of Precambrian, Hercynian, alpine and tectonic movements and events. Its hoisting alternated with long dormant periods. As a result of the activisation of the ancient Struma and Mesta faults during the Neogene and the Quaternary Pirin rose as a massive horst. The modern relief of Pirin was shaped in the Pleistocene when the mountain was subjected to alpine glaciation related to the global cooling. This glaciation occurred in parallel with that of the Alps. The process formed pointed pyramidal peaks, long U-shaped valley, cirques, moraine fields and vertical cliffs that characterise Pirin's contemporary appearance. These forms are most prominent at the north-eastern ridges of the mountain. Some lateral moraines may reach heights of more than 1100 m. The lower line of the glaciers was at 2200–2300 m. Karst landforms also shape Pirin's relief with ponors, swallow holes, caves, etc. The main Pirin ridge is clearly distinguished; it begins in Rila and passes through the Predel saddle as far