A theoretical study is made of the motion in the thermocline region of a large ocean. It is assumed that motion takes place under geostrophic and hydrostatic balance and that heat is transferred by convection only. Proper account is taken of the earth's spherical geometry. A class of solutions of the mathematical problem is derived and one of these, an inverse power solution, is discussed in detail. The solution does not satisfy all the details of the known physical situation but shows reasonable qualitative agreement with it....