At _Pendeen Cove_, the Geologist will meet with several phenomena well worthy his attention. At the junction of the Slate and Granite, veins of the latter will be observed traversing the former rock, and what is particularly worthy of notice, they may be seen emanating from a great mass of granite and passing into the schistose rock by which it is covered. One part of the cliff of this cove consists of large fragments of granite imbedded in clay and earth; the interstices of which are filled with white sand, which has been probably blown there from the beach; through this sand, water impregnated with iron is slowly percolating, the effect of which is the induration of the sand, and the formation of a _breccia_, which in some parts has acquired very considerable hardness. Before proceeding to the metalliferous district of Saint Just, we may observe that, if the traveller's object be to reach Saint Ives by the road along the cliffs, through the parish of _Zennor_, he will meet with a most cheerless country, but by no means destitute of geological interest. He ought particularly to examine a bold rocky promontory, called the "_Gurnard's Head_," where he will find a succession of beds of slaty felspar, hornblende rock, and greenstone. The geology of this headland has been accurately described by _Dr. Forbes_ in the second volume of the _Transactions of the Royal Geological Society of Cornwall_. _Polmear Cove_ ought also to be visited on account of the Granite veins, which are perhaps as singular and interesting as any of those already described.--But let us proceed to complete our examination of the coast of _Saint Just_. Many of the mines are situated on the very edge of the cliff, and are wrought to a considerable distance under the sea; but all communication to them is from land.[56] For a description of the numerous minerals found in this district,[57] we must refer the reader to the highly valuable paper by _Joseph Carne, Esq_. which is published in the second volume of the _Transactions of the Royal Geological Society of Cornwall_. We cannot, however, allow the mineralogist to pass _Trewellard_, without reminding him that, at this spot, _Axinite_ was first discovered in Cornwall, and that the most beautifully crystallized specimens of that mineral, scarcely inferior to those brought from Dauphiné, may still be procured here. In the cliff at _Huel Cock Carn_, a vein of this mineral, of a violet colour, three feet in width, may be traced for upwards of twenty yards; and in its vicinity there is to be found also a vein of _garnet rock_. _Apatite_, of a greyish-white colour, associated with _Hornblende_, may be seen in the same spot. In the slate rocks between _Huel Cock_ and Botallack, _Prehnite_ has lately been found, for the first time; it appears to form a small vein, which in one part is divided into two branches. Upon the discovery of the above mineral, says Mr. Joseph Carne, an expectation was naturally