366 REPORT— 1869. 



rounded, as in earlier times, and that the mineral-bearing rocks formed the 

 floor or backbone on which the later beds were laid down. This is the case 

 with Australian and Californian auriferous regions, the enormous denuda- 

 tion and consequent drifts of Tertiary age in the former case having laid 

 bare the backbone of the auriferous-bearing rock below. I have ah'eady shown 

 this to be the case with the Carboniferous Limestones of the west of England 

 and South Wales, where, in connexion with them, veins and pockets of 

 mineral-bearing lias are found. Liassic minerals, again, occur on what is 

 probably a continuation of the same great barrier, which, passing under the 

 south-eastern counties, crosses the channel to France, where they are seen 

 on a floor of granite. The outcrops of some of the limestones of i^^^orth 

 Wales and the north of England have been exposed to the influence of seas 

 certainly as late as the Coal-measures and the minerals found in the great 

 mining-districts of Cornwall, whether in the killas or the granite itself, are 

 found connected with, or resting upon, a great backbone of the latter rock. 



It is also worthy of remark that the conglomerates usually skirting the 

 edge of the limestone, which must long have been subject to the action of the 

 ocean, are large receptacles of iron, calamine, and lead, the veins in which 

 seldom, if ever, pass downwards into the hmestone, and which, though open 

 to the ocean, are cut oflpfrom sublimation beneath. The fissures in these great 

 lines of submarine mountains must necessarily have been chiefly filled with 

 marine matter, whether mineral or otherwise ; sometimes, where the mate- 

 rials were friable, supplied by the walls of the fissure, but perhaps oftener 

 derived. Wherever there has l3een a rapid filling up of the veins by a homo- 

 geneous material, the element of time is excluded, such as with the " dowky" 

 portions of the veins, and in such cases workable minerals are seldom found. 

 The same occurs where there is a sequence of deposition, and stratification 

 follows without a break in natural order. If the above view be correct, it 

 follows that the longer a fissure has been exposed to the influence of the 

 ocean, the greater will be the probability of a larger supply of minerals 

 therein. Where veins have been slowly filled, where they have been 

 cavernous, or by subsequent movements have been opened on several occa- 

 sions, where they contain conglomeratic infiUings, or have been kept open by 

 currents, favourable conditions to deposition occur ; and it is a well-known 

 law of mining that, at the junction where veins intersect, rich deposits or 

 pockets of minerals are most usually found, from the fact that at such points 

 there has been a scouring out of the fissures, and a longer time given for 

 precipitation. 



Palceontohgy of Mineral Veins. — The physical views I have suggested are 

 strongly supported by the investigations I have for some time been pursuing 

 regarding the presence of organic remains in mineral veins. During those 

 investigations I have examined materials derived from Carboniferous-lime- 

 stone veins and fissures from the mining-districts of Wharfedale, Wensley- 

 dale, Weardale, Teesdale, Swaledale, Alston Moor, Keswick, North and 

 South Wales, and Somersetshire ; and I am much indebted, for the facilities 

 they have aff'orded me in their several districts, to Lord Bolton and Messrs. 

 Wallace, Walton, Eddy, Bainbridge, Cain, Peart, Wasley, and Sopwith. 



It is remarkable, considering the enormous mine-workings and the quan- 

 tity of vein-stufi^ brought to the surface in every part of the world, that so 

 few notices of the presence of fossils in them should have occurred. In his 

 ' Elements of Geology,' p. 762, Sir Charles Lyell mentions that M. Virlet 

 had found a Gryphaja in a lead-mine near Semur in France, and that a 

 madrepore had been seen in a compact vein of cinnabar in Hungary, the pre- 



