The relations of geoid data from radar altimeter measurements (GEOS 3) to water depth and geochemical variations along the Mid-Atlantic Ridge are investigated. Eight geophysical lines across the ridge in the Atlantic Ocean were constructed approximately normal to the local ridge trend. Slopes of geoid per kilometer of topograhic relief show an asymmetry between the two sides of the ridge that generally is not matched by topography, which has better symmetry between the two flanks. Subtracting a regional field, based on previous work, produces residual geoid anomalies whose source must be in the earth's outer 600 km. The residual geoid anomalies of the North Atlantic show striking correlation with the axis of the Mid-Atlantic Ridge, but those in the South Atlantic do not. Instead, major positive residual geoid anomalies appear over the Rio Grande and Walvis ridges. Determination of slope S, residual geoid per million years crustal age, revleals that S increases with greater residual geoid anomaly and with higher (shallower) crestal ridge topography. The slope of 22 cm/m.y. west of the Azores high (near 38¿N) suggests that the anomalously high crestal residual geoid and depth anomalies may not be entirely of thermal origin, which may normally produce slopes only of about 8 cm/m.y. as found near 28¿N away from shallow ridge topography. To account for this difference in slopes simply by a variation in mantle temperature would require a difference of about 940¿C between the two sites, which appears excessive. Also, the decrease in topograhic height with crustal age away from the Azores high is much greater than predicted by theoretical cooling curves. Correlation of residual geoid anomalies with depth, geochemical variations along the length of the Mid-Atlantic Ridge, and the chemistry of the Rio Grande Rise and Walvis Ridge suggest that many regions of anomalous residual geoid and crestal depth values may be in large part a function of crustal thickness and density variations induced by plume intrusion and volcanism in addition to their transient thermal effects.