308 ANNUAL OF SCIENTIFIC DISCOVERY. 



involve an increase of specific gravity. On the other hand, if the 

 latter be decreased, the- volume must be increased in a still greater 

 proportion than the matter. Such is the case when silicates are de- 

 composed by carbonic acid. The specific gravity of the products of 

 decomposition being below that of the undecomposed minerals, their 

 volume must necessarily be greatly increased. If a mountain composed 

 of silicates be supposed to exist, its upper parts being exposed to 

 decomposition by carbonic acid and rain, then, if there be amorphous 

 silicate of alumina in the lower parts of this mountain, and if the sol- 

 uble products of decomposition (say alkaline silicates) were carried 

 downwards by means of water, crystals of feldspar may be produced 

 increasing the bulk of the mountain, and thus causing elevation. Not 

 only will the upper parts be thus elevated from below, but they will also 

 raise themselves, should their increase, through combination with water, 

 be greater than the decrease of bulk caused by substances carried down- 

 wards. Dr. Bischof cites the slow rising of portions of the Scandi- 

 navian area, where crystalline rocks containing silicates occur, as a 

 geological proof of the action of the cause explained above in the 

 elevation of rock masses ; adding that, where silicates are absent, as in 

 the south of Sweden, there has been no upheaval. Additional facts 

 and arguments will be found in No. 78 of the Journal of the Geological 

 Society, from which the foregoing notes have been selected. 



GEOLOGICAL SUMMARY. 



Decrease of the Supply of Copper. While the demand for copper is 

 yearly increasing, it would appear that the supply is decreasing. The 

 mines of England, Chili, and Cuba, all show diminished and diminish- 

 ing products. Thus, in 1856, the British copper mines produced yearly 

 24,527 tons of metal ; since which time their product has declined, 

 till 18(53, when their yield was only 14,247 tons, showing in seven 

 years a decrease of 1<>,2S() tons. The copper product of the United 

 States is on the contrary, rapidly increasing. 



Negative Eridence in Geology. Many disputes in geology are 

 founded upon the generally unwarrantable assumption that certain ani- 

 mals or plants could never have existed, because their remains have 

 not been found. It is, therefore, interesting to note a modern instance, 

 in which naturalists are without that kind of proof, furnished by a 

 specimen, of the existence of an enormous animal, apparently not un- 

 common. Dr. Gray, speaking of the Physetes, or Black fish of the 

 whalers, states in the 'Annals Net. Hist., "there is not a bone, nor 

 even a fragment of a bone, nor any part which can be proved to have 

 belonged to a specimen of this gigantic animal to be seen in any mu- 

 seum in Europe. This is the more remarkable, as the animal grows 

 to the length of more than 50 feet, is mentioned under the name of the 

 Black fish in almost all whaling voyages, and two specimens of it were 

 examined by Sibbold, having occurred on the coast of Scotland." 



Minute Geologic Krldi'iice. Mr. Edward Blyth has recently pointed 

 out the existence of two very distinct forms of deposit, which are 

 occasionally found on the teeth of fossil herbivora. By an examina- 

 tion of these the geologist is to some extent, enabled to determine 

 whether an animal lias been in the wild or domesticated condition. 

 " There is a small particular or character which generally distinguishes 



