Geology and Mineralogy. 309 



white oxide, non-volatile at a red heat, soluble in alkali solutions, 

 and reprecipitable by acids. Both oxide and sulphide are re- 

 duced by hydrogen and yield an element of a gray color and 

 moderate luster resembling arsenic, volatile at a full red heat, 

 somewhat more difficultly than antimony. Its vapor condenses in 

 small crystals resembling iodine. Heated in a current of chlorine 

 a white, easily volatile chloride is produced more volatile than 

 SbCl 5 and whose aqueous solution is precipitated white by H 2 S, 

 after acidifying. The author has not yet determined the atomic 

 weight, but suggests that the new element may fill the gap in the 

 periodic system between antimony and bismuth. — J3er. Berl. 

 Chem. Ges., xix, 210, February, 1886. g. f. b. 



II. Geology and Minekalogy. 



1. The Geology of Natural Gas in Pennsylvania and New 

 York • by C. A. Ashburner. — Mr. Ashburner observes that the 

 oil and gas-yielding regions of Pennsylvania are geologically 

 one. The borings yielding gas and oil go down to rocks in the 

 Carboniferous and Devonian. About 30 miles west to north- 

 west of Pittsburgh, at Smith's Ferry and Slippery Rock, the wells 

 reach the base of the Coal-measures and Berea grit. To the 

 north of Pittsburgh, 25 to 30 miles, they reach the Venango 

 (Devonian) sands; and 30 miles S. 65° E. of Pittsburgh at Pleas- 

 ant Unity, 31 S. 12° E, at Dunlap Creek, 45 m. to 48 m. south, 

 at Whiteley Creek and Dunkard Creek, they go down to the 

 Mahoning sandstone — the Lower Barren Coal-measures. The 

 occurrence of accumulations of gas is stated to depend on the 

 porosity of the rocks, the extent to which the rocks below the 

 porous sand rock are cracked; the dip of the beds and the posi- 

 tion of the anticlines and synclines ; the relative proportion of 

 water, oil and gas in the gas-bearing sand-rock ; and the pressure 

 under which the gas exists below. 



The dip of the beds is very small, generally but 20 to 35 feet 

 per mile, and that of 75 to 100 feet of the rarest occurrence. Of 

 the three principal horizons yielding gas, (a) the Venango first 

 oil-sand (or its probable representative) is 1800 to 1850 feet be- 

 low the Pittsburgh coal bed, and believed to be in the Catskill 

 formation; (b) the Sheffield gas-sand, the lowest in Warren Co., 

 is of Chemung age; and (c) the Bradford oil-sand, which is 1757 

 feet below the base of the Pottsville conglomerate (or the lowest 

 member of the Productive Coal-measures) is undoubtedly of 

 Chemung age. But gas is obtained also from other horizons, up 

 to that of the Mahoning sandstone, 500 feet above the Pittsburgh 

 coal-bed. The gas is believed to have been formed in beds underly- 

 ing the sand-rock from which it comes. The wells are commonly 

 along the axes of synclines, but this position, Mr. Ashburner says 

 is not universal. — Amer. Inst. Mining Engineers, Sept., 1885. 



To the above facts from Mr. Ashburner's report, it may be now 

 added that the very copious gas well recently opened at Findlay, 



