Since few, if any, conventional gravity surveys of the Jameson Area produced a significant gravity anomaly, an experimental high density gravity survey was conducted immediately following the field discovery. A station density of 15 per square mile was achieved. Great pains were taken to obtain higher than customary precision of each field measurement. Careful terrain corrections were applied. Maps of observed and residual gravity are presented.The subsequent drilling of some 36 field wells now provides an accurate reef map. This reef map is compared with the gravity anomaly to bring out the degree of correlation which may be expected from other similar reefs.