70 REPORT 1864. 



then, by way of illustration, worked out the physical geography of the Cretaceous 

 period, using as data the rocks of the eastern and northern counties ; and, ha^-ing 

 considered the effects of these physical revolutions upon the fauna of the ocean 

 floor, it was concluded that the operation of elevation and depression, in the ways 

 pointed out, might have produced all the phenomena of existing life-provinces on 

 land and by sea, and similar life-provinces in the seas of past time. It was then 

 shown that the breaks between strata do not generally indicate denudation or breaks 

 in time, but merely upheaval or depression of old lands, bringing into wear new 

 rock-material and causing the immigi-ation of a new pro\"ince of marine life. Mr. 

 Seeley concluded by contesting the idea that extinct species could tell anything 

 about the phj-sical conditions imder which they lived. All the different distribution 

 of existing analogues, as compared with their fossU antetypes, was the result of 

 migration of species, and not of changing climate. 



On the Thermal Water of the Clifford Amalgamated Mines of Cornwall. 

 By W. W. Smyth, M.A., F.B.S., F.G.S. 



The North, or Hot Lode of the Cliflbrd Mines, formerly known as that of the 

 United Mines, is one of a group of east and west veins which are encased in the 

 clay-slate or killas, on the east of the granite hill of Cam Marth. Mr. Kenwood's 

 observations, a quarter of a century ago, showed that water had been met with at 

 several places, varying fi'oni 1104 to 12G0 feet deep, of the temperature of from 90° 

 to 100° Fahr. In 1839 a cross-cut at the United Mines intersected a large feeder 

 of very hot water, and with it a rich lode of copper pyrites, which has since been 

 continuously worked eastward and downward. The author found, in 1855, the 

 chief spring welling upwards in a level 1510 feet deep, with a temperature of 114°. 

 In July 1864, from the extension of the excavations in depth and eastward, he 

 foimd, at 1620 feet deep, that three themiometers placed in the water marked 122°. 

 The lode at this point was of moderate size, and improving as it was followed east ; 

 being in the 220-fathom level (1590 feet deep fi-om surface) 12 to 16 feet wide, and 

 yielding a very large amount of rich copper ore. The spring is estimated to give 

 150 gallons per minute ; and although chloride of sodiimi is abundant in it, the 

 low percentage of magnesian salts, as compared with sea-water, as well as the 

 situation of the lode, render it unlikely that the water is derived directly from the 

 sea. The absence of sulphates of iron and copper, as shown by Prof. Miller's ana- 

 lysis, seems to set aside the hypothesis of the heat being due to the decomposition 

 of the sulphides. 



The exceptionally high temperature of the water was not observable when the 

 workings were shallow, partly perhaps owing to the closer texture of the vein, and 

 partly to the large area over which the warm water seems to have been diffused. 



An increase of depth of 180 feet in the point of issue of the water had raised the 

 temperature 8° Fahr., showing the remarkable increment of 1 degxee for 22^ feet. 



On the Conclusion to be draiun from the Physical Structure of some Meteorites. 

 By H. C. SoRBY, F.li.S., F.G.S. 

 The author had elsewhere * shown that the earliest condition of meteorites of 

 which their microscopical structure furnishes evidence was that of igneous fusion. 

 There are, however, some, like the Pallas iron, consisting of a mixture of iron and 

 olivine, which apparently strongly oppose this view, if we merely judge from what 

 occurs when such substances are melted artificially ; for then the iron, being so 

 much more dense, would sink to the bottom, and the olivine rise to the top, like 

 slag in a furnace. The object of the paper was, however, to show that this dif- 

 ference in density depends on the force of gravitation, and that, on the smface of a 

 small planetary body, or towards the interior of a larger, iron and olivine might 

 remain mixed in a state of fusion long enough to allow of gradual crystal- 

 lization. Such meteorites should therefore be considered evidence of fusion where 

 the force of gravitation was very snuxll ; and this conclusion may be valuable in 

 decidino' between rival theories of their origfin. 



I 



* Proceed, Eoy. Soc. vol. xiii. p. 333. 



