HYBRID RESISTANCE CONTROLLED BY H-2 REGION: CORRECTION OF DATA.

Ostenso says in his fourth paragraph, but so there are in continental areas, as he shows in the Lake Superior area, where areas of lower magnetic amplitude 50 miles across are observed. Although "positive proof" of our conclusions has not been possible, we realize that progress is made by offering suggestions which are, at the least, interesting and provocative, and which will lead to useful discussion and to the acquisition of more data aimed toward the solution of the fundamental question of the essential differences between oceanic and continental crust. In no case do we intend to express a "sweeping disregard" for the data from other geophysical disciplines, although we do suggest that in a complex region, methods such as dispersion of earthquake waves and phase transmission studies may not be as helpful as magnetic data, which may be more diagnostic of the existing lithology of large crustal blocks. ELIZABETH R. KING ISIDORE ZIETZ U.S. Geological Survey, Washington, D.C. LEROY R. ALLDREDGE U.S. Coast and Geodetic Survey, Washington, D.C.