GEOLOGY, BY DR. BOASE. The portion of this parish around the church, and the various insulated portions, are situated on magnesian rocks; the most abundant variety of which is serpentine. This rock is generally of a red colour, but this is evidently in some cases derived from a partial chemical change. In its perfect state this serpentine is generally of a dark-green, with shining scales of diallage, which are commonly of a bronze colour, and at other times of a fine green. The serpentine at Cadgwith may be seen to pass gradually into a schistose rock of a dark bottle-green, and very glassy and spangled on the surface of its lamellæ. This slate is generally called greenstone, but it differs therefrom, and consequently requires a distinct appellation. At Cagar there is a quarry in the serpentine; and at Kennick Cove adjoining, many varieties of these rocks may be obtained. GULVAL. HALS. Is situate in the hundred of Penwith, and hath upon the north Ludgvan, south the Mount’s Bay, west Maddaran, east St. Hilary. In the time of William the Conqueror’s survey of lands, anno Dom. 1087, this parish, I suppose, passed in tax under the jurisdiction of Ludgvan. In the Inquisition and Taxation of Benefices in Cornwall, by the Bishops of Lincoln and Winchester, 1294, Ecclesia de Laneseley, in decanatu de Penwith, appropriata priori Sancti Germani, is valued lxvi_s._ viii_d._ Vicar ibidem, xx_s._ At which time it seems it was but a Vicarage church; the garb impropriated, though since restored. Neither was the name of Gulval then mentioned. However, in Wolsey’s Inquisition, 1521, it is rated by the name of Gulval, also Laneseley, 6_l._ 11_s._ 0½_d._ The patronage was formerly in the Prior of St. German’s, now in the crown. The incumbent Penhellick; and the parish rated to the 4_s._ per pound Land Tax, 1696, by the name of Gulval, 120_l._