IN a note on the Hyrcanian Sea (vide NATURE, vol. xii., p. 51), it was stated that the waters of Aral, whose surface is now about 159 feet above sea level,formerly overflowed at their S.W. corner, when the lake possessed a depth of 50 feet more than at present. It is certain that the spur of Ust Urt, which formed a waste weir at the point in question, has been lowered by the action of escaping water; and the level at which the overflow took place, in the first instance, was probably some few feet higher than the figure of 209 which has been given. The greatest height ever reached by the water contained in the basin of Lake Aral may therefore be said with tolerable accuracy to be about 220 feet above the sea.