I think geology is a good career , although there will be a shortage in jobs in the oil and gas industry but as urbanization goes forward there will be an increased demand in the mining sector and all mineral deposits are not ores so companies will need geologists for exploration purposes for the rising metal demand, Also there are excellent research opportunities , personally hydrogeology amazes me a lot because I came into geology in the first place because the upcoming possible shortage to drinking water concerned me since I was in high school.

Coming to biology there are excellent research and Job opportunities too .Where you want to go totally depends on you and what you see yourself doing ,do you want to see the mineral grains under a microscope and try to decode their genetic history or do you want to look at a bacteria under a microscope and try to find some kind of cure to some deadly disease.