Geology is an inter-discipliry science and the advance made in its understanding is based on valuable research contributed from the other sciences. This has given rise to a host of specialised fields such as environmental geology, marine geology, photogeology and mining geology, to me a few. This book has been written for the first year students of Geology and also for those who have opted for Geology as one of their subjects for competitive examitions such as UPSC, MPSC and others.