Introduction

Rock art is a global phenomenon. It forms the archaic visual manifestations of hominins on bare surface of rocks, which have survived the vagaries of time. Other archaic forms of human cultural activities such as dance, music, songs, thoughts, ideas, language, etc could not survive. It means rock art is one of the many aspects of human creativity and cultural activities which has survived and available to us, hence is a very important source for understanding the cognitive and cultural development of the early hominins.

The rock art and rock art sites are the wonderful legacy the nature, the pioneers and authors of rock art had left for humanity (Kumar 2011a, 2011b, 2014). The theme of the figures in rock art generally not used to be a depiction of day-to-day life activities or socio-cultural and natural environment as seen by their authors. Rather, it reflects the reality as perceived by their authors in particular and the related community in general, and also the human behaviour developed in the light of so earned wisdom at different stages in human history. Birth and death are two important realities of life understood by the hominins and are associated with different kind of ritual practices and ceremonies in different communities in different parts of the world. In between these two ends of human life, birth and death, hominins have been making their best efforts to sustain, maintain and celebrate life in a particular environment. In this process of struggle and celebration of life he manifested his creative ideas and thoughts in the form of rock art (Kumar 2009a).

Thus, rock art forms a wonderful and valuable tool for understanding the cognitive and cultural development of the hominins in the perspective of their adventurous zeal and creative spirit right from the beginning of human history.

Setting of rock art sites in different geo-climatic zones

India is one of the three countries having the richest treasures of rock art in the world.  Other two are Australia and South Africa, Brazil, Saudi Arabia and China are also emerging as countries having rich treasures of rock art.

Rock art sites have been reported from throughout India in different geological, geographical and climatic zones particularly in the areas of sedimentary, metamorphosed and igneous rocks; from Ladhak in the Himalayas in the north to Kerala and Tamil Nadu in the south, from Arunachal Pradesh in the east to Badmer in the Thar Desert in Rajasthan in the west (Fig.1). So far rock art sites have not been reported from Trapian regions, but I am sure an intensive exploration in these regions in future will definitely bear fruits, especially discoveries in the form of petroglyphs. It is evident from the accidental observation by the author while publishing the article of Satish Lalit in Purakala (Lalit 2013, Fig 10). In that paper Lalit published a deccan trap boulder bearing petroglyphs while presenting the discovery of rock art on laterite in Sindhudurg , the southernmost district of Maharashtra adjoining Goa. Now the boulder does not exist, as it has been destroyed during the construction of the road (Lalit 2013). Prior to it I was shown some cupules on Deccan trap bed rock in the campus of Deccan College, Pune in 1995.

Rock art sites and complexes are found generally on the plateaus and hill slopes and hill tops (Fig. 2), in the valleys and river gorges having rock shelters (Fig. 3), open rock surface  and boulders (Fig. 4 and 5) and caves, which were used by humans for creation of rock art (sometimes for habitation also). These are located in the regions where nature unveils its serene beauty in the form of lush green forests full of vegetable food, wild fauna and plenty of natural resources including the most essential water for survival of life. At the same time such sites have been giving open invitation for exploration to adventurous minds and inquisitive zeal of the humans.

Rock painting sites are rich in the regions of sedimentary rocks having the capacity to withhold paints such as sandstone, quartzite, limestone, etc. Igneous rocks being very hard and compact in nature have comparatively less capacity to withhold pigments, hence in such regions chances of the survival of early rock paintings are less as compared to petroglyphs. Further, rock art, particularly rock paintings can survive for comparatively longer time in the caves as in Europe where because of their closed environment the climate remains mostly constant and surface bearing rock paintings secure. It also applies to rock shelters where the environment is secure.

Because of the above-discussed geological, natural and climatic factors, hills, valleys and plateaus in India with exposed sedimentary rocks, especially sandstone and quartzite ones, are usually having boulders, rock shelters and caves. These have been formed due to natural weathering of soft strata in them. Most of the shelters are in the walls of canyons cut by rivers and nalas or in the steep sides of mesas and hilly cliffs from which the surrounding country has been eroded away as in Modi and associated area in Chambal valley and hilly cliffs in central India. The principal exception to these is found on low mountains as at Bhimbetka where a stratum of rock on top has been separated by differential erosion in to huge boulders whose lower side have been eroded by wind and water in to habitable shelter.

In some cases the shelters are well up on one side of the gorge as in the Chambal gorge at Gandhisagar,  Chibbad nala near Bhanpura, Bhaldaria near Mirzapur and Chachaifall near Rewa, with thorn trees, scrub and vines clinging to the rock and a stream far below. In other cases, the shelters are in large boulders at the edge of a plain as at Adamgarh in Hoshangabad district or on the hilly slope as in the Gawilgarh Hills in Betul district in Madhya Pradesh.  At Pachmarhi many of the shelters are at the bottom of the gorge so heavily forested that sunlight filters through to the shelters only at the noon hours, and some shelters are on the top of the hills visible from distance. The size of the rock shelters varies from very big 60-100 m (or even much bigger than it as the Samdha rock shelter near Sarmathura , Dholpur district, Rajasthan in Chambal valley) to very small ones, 2-3 m only.

Walls of so formed rock shelters and caves and open surface of boulders and plateau-beds were used as canvas for execution of rock art in different periods of human history. In rock shelters roof has also been used for this purpose. Thus, early man created rich rock art galleries in the beautiful lap of the Nature.

Generally rolling undulating rugged terrain and exposed igneous rocks form the topography of the peninsular India. These rocks, especially granite and dolerite, weather in the form of piles of boulders, rounded by erosion in due course of time. Hence, at different places they are in different state of roundness. At Kishkindha in Karnataka on both the sides of river Tungabhadra the hills are laden with granite boulders in their varying size (Fig. 6). From distance they appear to have been arranged one above the other as if done by some powerful agency. This phenomenon gives a spectacular view to the landscape and is a common feature in the granite and dolerite regions in the peninsular India and also in other parts of the country as in Rajasthan and Gujarat. Weathering of such boulders made rock shelters in them, which are of different size and dimensions. Reshuffling of these boulders because of earthquakes or other movements in the earth resulted in the formation of pseudo-caves such as Edekkal cave in Kerala. So formed rock shelters, pseudo caves and boulders in open on saddles, plateaus or hilltops were used by humans for creation of rock art. The areas surrounding them and sometimes some of them also were inhabited in different times of human history right from the beginning. These sites have been providing their habitants a commanding view of the otherwise flat surrounding country.

Thus, because of the nature of rocks and climatic factors discussed above mostly petroglyphs are found in the coastal areas. Early rock paintings cannot survive in the hot and humid climate of the coastal region. It does not mean that they were not there. As we go inside the main land away from the coastal regions we start getting early rock paintings on sedimentary rocks, especially on quartzite rocks in Karnataka and Andhra Pradesh. Given the same environmental conditions the chances of survival of early petroglyphs are more as compared to early rock paintings. Because of the non-porous nature of granite and other igneous rocks early paintings cannot survive on them for longer time. Hence, most of the early rock art on igneous rocks in southern India, especially in Kerala and Tamil Nadu, is in the form of petroglyphs.

No one could have expected rock art in the lateritic formations on the Western Ghats. But Goa presents a unique example in the world as here petroglyphs have been executed on sloping bed of laterite. It is obvious as the western- coasts are full of laterite deposits. Recently Sindhudurg, the southernmost district of Maharashtra adjoining the borders of Goa has also yielded petroglyphs sites on laterite and also on a Trapian boulder (Lalit 2013). The future can witness such many more astonishing discoveries of rock art from unexpected locations.

Because of the geographical, geological and climatic reasons discussed above, the inner part of India with the above features is very rich in rock art, especially in rock paintings, as compared to the Himalayas where rocks are fragile and climate is cold and humid and also in the coastal areas that are hot and humid. In these areas chances of the survival of early rock paintings are very less as compared to petroglyphs. Hence, mostly petroglyph sites have been reported from these regions.

Understanding the setting, location and environment of a rock art site or a rock art site complex is extremely necessary for understanding rock art properly, so also the application of taphonomic principles on it for its survival. Because of the importance of the location of a particular rock shelter or a site and that of a particular surface therein, rock art has been created one above the other for generations together. It resulted in superimpositions of the figures and motifs, sometimes very complex multilayer ones. In some cases of superimpositions the early figures have become very faint because of the effect of climate and natural factors. Their decipherment becomes a tedious task and their photographs do not help.  Therefore, one needs to draw its faithful copy on the site itself. Sometimes rock art is found created on very high locations and places very difficult to reach there.

Thus, a rock art site unfolds its secrets slowly. Sometimes we have to visit the site again and again and every time we would be surprised by new discoveries. One needs dedication and passion to explore, analyse and understand rock art. Sometimes one feels that one life is not sufficient to accomplish the task.