Nallamala Hills Andhra Pradesh

The Nallamalas (Telugu: నల్లమల్ల కొండలు) (also called the Nallamalla Range) are a section of the Eastern Ghats which stretch primarily over Kurnool, Mahabubnagar, Guntur, Prakasam and Kadapa districts of the state of Andhra Pradesh, India. They run in a nearly north-south alignment, parallel to the Coromandel Coast for close to 430 km between the rivers, Krishna and Pennar. Its northern boundaries are marked by the flat Palnadu basin while in the south it merges with the Tirupati hills. An extremely old system, the hills have been extensively weathered and eroded over the years. The average elevation today is about 520 m which reaches 1100 m at Bhairani Konda and 1048 m at Gundla Brahmeswara. Both of these peaks are in a north westerly direction from the town of Cumbum. There are also many other peaks above 800 m. Over a period of History conjoining all the three present states of Karnataka, Tamil Nadu and Andhra Pradesh, Maharashtra, a legend survives that "Nallamalla" is a treasure trove in the region. The Legend continues to a large extent, since some of the tribes living within Nallamalla have practically refused to take up civil living and are hostile towards a non-tribals or rival tribals, and also because these ranges are largely unexplored and stay unexplored even till date. The difficulty of finding in this terrain is made more clear that even with sophisticated finding equipments, the Late Chief Minister of Andhra Pradesh practically laid dead and unfound for more than 24 hours in the helicopter crash that killed him.

Geology
The rocks of the Nallamala ranges belong to the Kadapa system which is a series some 20,000 ft. thick.The primary rocks are Quartzite overlaid with an irregular slaty formation. Some sandstone is also to be found. The rocks here are very irregular and soft in texture thus rendering commercial exploitation impossible. These rocks are among the oldest in the world and have been formed as a result of large scale volcanic activity hundreds of millions of years ago. The evidence of the volcanic forces are evident in the foldings into which the rocks have been forced, in some cases the folds have been completely inverted.

Climate
The Nallamalas have a rather warm to hot climate throughout the year. Rainfall averages about 90 cm and is concentrated in the months of the South West Monsoon (June–September). The fissured rocks prevent any water from percolating underground and hence most of the discharge runs off as mountain streams to join the Gundlakamma River, the largest river to arise in these hills. Winters are mostly cool and dry with the average temperature around 25 degrees celsius.