SCIENTIFIC NEWS. . 31J 



veins that occur indifferent great rock-formations, beginning 

 with granite, and ending with the newest ftcetz trap forma- 

 tion. He next explained the mode of formation of these 

 veins. When describing the contemporaneous veins, that 

 occur in gneiss, he remarked, that certain varieties of veni- 

 genous gneiss bear a striking resemblance to granite, and 

 hence have been frequently confounded with it. This led 

 him to point out the characters by which true granite veins 

 are distinguished from veins of granitic gneiss. 



As connected with this part of the subject he examined the Ramark on the 

 facts, on which the Huttonian theory of granite is founded ; t h" t ry niaft 

 and proved by a detail of his examination of the appearances 

 described by Dr. Hutton, Professor Playfair, and others, that 

 the supposed granite veins, shooting from subjacent granite 

 into superincumbent rocks, are merely veins of granitic 

 gneiss accidentally in contact with granite. 



Professor Jameson has just published the third volume of p ro fessorjame. 

 his System of Mineralogy, under the title Elements of Geog- son's Elements 

 nosy. The contents of this valuable work are as follows, or Scfvol" ofhi* 

 Chap. I, Description of the surface of the earth; chap, 2, System of 

 Effects of water on the surface of the earth ; chap. 3, Inter- inera Q ^ y ' 

 nal structure of the earth ; chap. 4, General account of the 

 different formations in regard to their succession and strati- 

 fication, and this illustrated by a short description of the 

 Ilartz and Saxon Erzebirge; chap. 5. Theory of the dimi- 

 nution of the waters of the globe — Description of overlaying 

 formations — An investigation of the original contents of the 

 waters of the globe, during the different periods of the earth's 

 formation. The division of rocks into five classes; chap. 

 6, class 1, Primitive rocks ; chap. 7, class 2, Transition rocks, 

 chap. 8, class 3, Floetz rocks ; chap. 9, class 4, Alluvial 

 rocks; chap. 10, class 5, Volcanic rocks; chap. 11, 

 Mineral repositories; chap. 12, Relative age of metals, 

 and general inferences. These are followed by a table of 

 32 pages, containing the relative antiquity and geognostic re- 

 lations of simple minerals : also an extensive table of the 



most 



