GEOLOGY. 321 



ON THE DE-BITUMKNIZATION OF COAL. 



At a meeting of the Philadelphia Academy, May 1859, Dr. Emmons re- 

 marked, that the de-bitumenization of coal was effected through the agency 

 of heat, but he did not think that the de-bitumenization of anthracite was due 

 to heat emanating from an incandescent body, whether that body be in- 

 jected trap or other pyrocrystalline rocks. In his opinion the heat which 

 de-bitumenized the coal of the anthracite region was disengaged or generated 

 by the collision of the rocks enclosing it at the time of their upheaval. In 

 support of this view he referred to the correlation of forces, the equivalent 

 of heat, etc. ; and stated he found by experiment, a year ago, that the vola- 

 tile matter of the bituminous slates of North Carolina began to come off at 

 35CP, and that it was all driven off as paraphine, and all at about- COS . Hence 

 he inferred that coals are de-bitumenized at low temperatures, and that in- 

 tense ignition is not required. 



ORIGIN OF BITUMINOUS SCHISTS. 



M. Reviere communicated to the French Academy, Oct. 23, 18-"8, a curious 

 observation, which had led him to a new theory of the origin of certain 

 rocks which are found to contain a small quantity of combustible matter. 

 He was first struck by the resemblance between these rocks and the earth 

 saturated with ordinary coal-gas by the leakage of the pipes which convey 

 it. By a series of experiments he found, 



1st. That the soil surrounding the pipe was, in certain circumstances, and 

 after some time, more or less impregnated with carbon and bitumen, so as 

 to become sometimes very combustible, and as black as impure coal. 



2d. That the nature of the soil had much influence on the absorption; 

 thus, whilst a clayey, slightly damp soil charged with vegetable or animal 

 debris favored this absorption, it was, on the contrary, but slight in dry 

 sand. 



3d. That the thickness of the upper strata favored absorption. 



4th. That it was greater near the cracks and stratification joints. 



5th. That the absorbing materials increase in weight, and sometimes in 

 bulk. 



6th. That the vegetable matters were gradually converted into carbon 

 more or less bituminous according to circumstances. 



7th. That the ferruginous materials were altered, more or less converted 

 into oxides, sulphates, or sulphites; and that they would probably have 

 been converted into sulphurets and carbonates, had the gas been less puri- 

 fied, and had the action been sufficiently prolonged and the circumstances 

 favorable. 



ON THE SO-CALLED " TALCOSE SCHISTS " OF* VERMONT, ETC. 



At the meeting of the American Association for the Promotion of Science, 

 Mr. C. H. Hitchcock stated that the geological surveys of the various States 

 have made known the existence of a broad belt of rocks from Canada to 

 Georgia, consisting of green schists, denominated talcose, associated with 

 gneiss. This implies the presence of the mineral talc, which contains a large 

 percentage of magnesia. Recent investigations had, however, rendered it 

 probable that the character of the whole belt was aluminous rather than 

 maynesian. Mr. T. S. Hunt, of Montreal, had analyzed some of these rocks 



