I aspirant,
The basic eligibility criteria for you is that you need to pass bsc examination in geology and any of the following two subjects-physics, chemistry, maths, botany, zoology, environment science(including geology). Marks criteria varies from college to college. You need to have geology as a subject in bsc for doing msc since you have not kept geology you wont be able to do msc in geology as you dont pass the eligibility criteria. But you can go for MA in geology as you pass the eligibility criteria for it. Hope you are clear with it

Dear Debasmita, yes you can do your MA(Masters) in Geology. MA Geology is a 2- year post graduate degree program. The average course fee charged by institutes ranges from INR 2k to 50k.

Students who have completed their graduation and have B.A. or B.Sc. degree or any other equivalent qualification in any stream with minimum 50% marks (5% relaxation for reserved categories) are eligible to apply for this course.

Admission is based either on the entrance examination conducted by the concerned university or total score secured in the graduation and its conformity with a specific range of cut-off list. Some institutes may conduct a round of Personal Interview for screening the candidates. A few of them also provide direct admission considering the score obtained in graduation or the qualifying examination.

All the best. 

Feel free to ask for any query.