"A very considerable portion of the northern coast of Cornwall, is covered with a calcareous sand, consisting of minute particles of comminuted shells. That part which lies between St. Ives and Padstow is more immediately the subject of the present inquiry; a tract which, with a few exceptions, is entirely covered with this species of sand; and which in some places, has accumulated in quantities so great as to have formed hills of from forty to sixty feet in elevation. A considerable area, for instance, in the parishes of Gwythian and Phillack has been thus desolated, and several churches have been inundated. In digging into these sand hills, or upon the occasional removal of some part of them by the winds, the remains of houses may be seen; and in some places, where the churchyards have been overwhelmed, a great number of human bones may be found. The sand is supposed to have been originally brought from the sea by hurricanes, probably at a remote period."----"The sand first appears in a slight but increasing state of aggregation on several parts of the shore in the bay of St. Ives; but on approaching the Gwythian river, it becomes more extensive and indurated. On the shore opposite to Godrevy Island, an immense mass of it occurs, of more than a hundred feet in length, and from twelve to twenty feet in depth, containing entire shells and fragments of clay slate; it is singular that the whole mass assumes a striking appearance of stratification. In some places it appears that attempts have been made to separate it, probably for the purpose of building; for several old houses in Gwythian are built of it."----"It is around the promontory of New Kaye that the most extensive formation of sandstone takes place. Here it may be seen in different stages of induration; from a state in which it is too friable to be detached from the rock upon which it reposes, to a hardness so considerable, that it requires a very violent blow from a sledge to break it."----"But it is on the western side of the promontory of New Kaye, in Fistril Bay, that the geologist will be most struck with the formation; for here no other rock is in sight. The cliffs, which are high, and extend for several miles, are entirely composed of it."----"The beach is covered with disjointed fragments, which have been detached from the cliff above, many of which weigh two or three tons." There are three modes by which Dr. Paris conceives the lapidification of calcareous sand may be effected. 1st. "By the percolation of water through a hill of calcareous sand, by which it becomes impregnated with carbonate of lime." 2d. "The percolation of water through strata containing pyritical substances, by which it becomes impregnated with sulphuric salts." 3d. "The percolation of water through decomposing slate, or any ferruginous strata, by which it becomes impregnated with iron alumina, and other mineral matter." ART. V. _Localities of Minerals._