Lynn McCorrnack, age 12, of Yonkers, Now York, for the question;

How does a geologist locate oil under the; ground

If you discovered a sure way to locate oil, you would become very popular,. For no one can point down and say for sure that there is a pool or layer of oil soaked rocks down here or there. Even trained experts can say only there is likely to be a supply of precious oil buried somewhere around here; or there.

These experts are geologists. They study the history of the earths crust in various places. This information tells them where oil is likely to be found. For layers of rock types on and under the surface toll the geologist what happened here in ages past. With patient detective work, they piece together the history of a likely area maybe, 50, 100 or 200 million years into the past.

They are interested in finding a period in this history when conditions were right for forming oil. Certain layers of rock show that an area was once flooded by ancient seas. Then it became dry land. In time, the slime of the, old seabed, teeming with the fatty ooze of countless tiny sea creatures, could become a reservoir of deeply buried oil. These are the likely places to drill. But even so, the expensive drills may just miss the reservoir. Countless dollars would be saved if someone knew a sure way to drill and find oil.