342 SCIENTIFIC RECORD FOR 1882. 



iug have distorted and broken up the magnesian strata, and have 

 forced the tough and hard rock through or along fissures in the surround- 

 ing and more yielding strata, thus giving rise to the deceptive appear- 

 ance of intrusion. Stapft adduces evidence to show that these displace- 

 ments took place while these rocks were in the solid state, and cites the 

 existence of polished and striated surfaces, and of fissures filled with a 

 friction -breccia as evidence of this. In parts of the section at the St. 

 Gothard, the conformable interstratification of the serpentine with other 

 rocks is apparent. 



In some parts of Italy, notably in Tuscany and Liguria, are areas oj 

 serpentine which, appearing in regions among Tertiary strata, have 

 been by most geologists regarded as eruptive and i)osterior to these. 

 These serpentines are, however, accompanied by euphotides and schist- 

 ose rocks, and are admitted to resemble very closely the serpentines 

 wliich, with similar associations, are found in the pietre verdi or Hu- 

 ronian series of northern Italy. Gastaldi, as is well known, asserted 

 that these so-called newer and eruptive serpentines were but portions of 

 this underlying ancient series, which, as the result of uplifts, faults, and 

 erosions, are exijosed in the midst of more recent deposits. This opinion, 

 although much controverted, is shared by Jervis and by Hunt. The 

 latter, from his examinations of these rocks, in parts of Liguria and of 

 Tuscany, maintains that this view is the only one in accordance with 

 the facts. 



ANTHRACITE COAL. 



The generally received opinion that anthracite has been formed by a 

 subsequent alteration of bituminous coal, and is in some way connected 

 with disturbance of the inclosing strata, has been contested. The present 

 writer has long maintained that differences connected with the original 

 conditions of formation have given rise to the anthracite, bituminous, and 

 semi-bituminous coals of Pennsylvania, which "have been the result of 

 decompositions going on at ordinary temperatures." Later studies by 

 Franklin Piatt, of the geological survey of that State (Eeport G- G.), 

 are in point. In Sullivan County, to the northwest of the great anthra- 

 cite region, where the strata are affected only by broad, gentle undula- 

 tions, is a small outlying coal-area known as the Bernice or Loyalsock 

 basin. Here are exi)osed two coal-seams near the base of the measures. 

 The upper one, eleven feet thick, lying beneath eighty feet or more of 

 thin-bedded sandstones, is an anthracite, while sixty-five feet below is a 

 seam of two feet, beneath five feet of shale, which has the composition of a 

 semi-bituminous coal. The ratio of volatile matters to the fixed carbon, 

 deducting ash, water, and sulphur, ivS, according to Mr. Creatb, for the 

 first, 1 : 10.289 ; and for the second, 1 : 4.132. Another seam in this 

 basin not certainly identified with either of the above consists of two 

 benches separated by six feet of shale, the upper bench being semi- 

 bituminous and the lower an anthracite, with ratios, respectively, 1:2.527 



