INTRODUCTION
The data collected during the field studies, are needed to be documented. The data are plotted on a topographical map, pertaining to the area undertaken for the geological mapping exercise. The topographical maps, therefore constitute the starting point of the field studies. These maps depict the surficial relief of the earth. It is important to remember, that, fundamentally, the hills, the valleys, the plane round, are all made up of rocks. The geologist is inquisitive about them (rocks). It is therefore possible to get a broad and a general idea about the kind of the rocks, from the geomorphological features (like the hills, the valleys etc.). It is appropriate therefore, to devote a separate chapter to describe the correlation between the geomorphology and the crustal rocks. Besides the topographical maps, in the latter half of the 20th century, the aerial photographs and the satellite imageries, are being used extensively in the geological investigations. The information gathered from the aerial photographs, and the satellite imageries, also helps to identify the rocks exposed on the surface of the earth. The topographical maps, the aerial photographs, and the satellite imageries, constitute the FIRST COMPONENT of the field studies. Besides the topographical maps, the aerial photographs, and the satellite imageries, the geologist needs a number instruments. No field work is possible without the proper accompaniments of hammers, clinometer compass, pocket lens, pen-knife, and so on. Out of these items, the compass, the pocket lens, and the hammers, are indispensable, because these constitute the most essential ones. All these have been therefore categorized as composing the SECOND COMPONENT of the field studies. In the following paragraphs, a detailed account of the two components, has been presented.
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SUMMARY
Field studies are extremely important. These form the basis for the later laboratory investigations. Incorrect and an incomplete field data, result in an erroneous assessment of the composition of the crustal rocks. The land surface is extremely small, as compared to that of the oceanic water. Large parts of the land surface, are covered by forests, soils. The outcrops of rocks are meagre. Therefore efforts should be made to study all the outcrops, during the field mapping exercise.
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