Ir is a general maxim of the common law, that whatever is in a direct line between the surface of any land and the centre of the earth belongs to the owner of the surface. Hence the owner of freehold lands has a right to all the minerals underneath the surface, with the exception of royal mines, which it is needless to refer to further, as the royal prerogative does not clash with the property in coal.
This general rule, however, is capable of being modified by showing a title distinct from that to the surface. It is well known that in mineral districts the ownership of the surface is often vested in one person, and that of the minerals in another. Even one seam of coal under the same surface may belong to one person, and another seam to another. Such a claim to minerals, being adverse to the owner of the surface, must be proved distinctly, when called