towards the north-east. The anticlinal fault of Charnwood Forest, so far as known, satisfies these conditions, and it is highly probable that the earthquake was caused by a slip of this fault. The beginning of the sound preceded that of the shock in all parts of the disturbed area; the end of the sound followed that of the shock in the central district and in the neighbourhood of the minor axis, but preceded it near the end of the major axis. Thus the sound ap parently outraced the shock in the

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... direction of the major axis, but not in that of the minor axis. These time-relations of the sound and shock can be readily explained if the area over which the fault-slip took place were several miles in length, for the sound in all prob ability is due to small and rapid vibrations proceeding chiefly from the margins of that area.