Whenever it shall appear (a)that the occupant or those under whom he claims entered into the possession of premises under claim of title, exclusive of any other right, founding such claim upon a written instrument as being a conveyance of the premises in question or upon the decree or judgment of a competent court and (b) that there has been a continued occupation and possession of the premises, or of some part of such premises, included in such instrument, decree or judgment under such claim for ten years, the premises so included shall be deemed to have been held adversely, except that when the premises so included consist of a tract divided into lots, the possession of one lot shall not be deemed a possession of any other lot of the same tract.