200 ANNUAL RECOED OF SCIENCE AND INDUSTRY. 



tion of which had been previously procured by Professor F. 

 B. Meek and Mr. Henry Bannister. This he names Agathan- 

 mas sylvestris. 5Z>, JSTovember^ 1872, 669. 



UPPER COAL MEASURES WEST OF THE ALLEGHANIES. 



In a recent paper on the "Upper Coal Measures west of 

 the Alleghanies" (or the group of strata including the Pitts- 

 burgh coal and the beds above it), Professor J. J. Stevenson 

 holds that during their period the general condition was one 

 of subsidence, interrupted by longer or shorter intervals of 

 repose. During subsidence the great marsh, now appearing 

 as the Pittsburgh coal-bed, crept u]3 the shore ; but in each of 

 the longer intervals of repose it pushed out, seaward, upon 

 the advancing land of the eastern shore of the inland sea, and 

 thus gave rise to the successive beds above it. The Appa- 

 lachian coal-field and that of Indiana and Illinois were prob- 

 ably never united, and the bituminous trough of the former 

 west of the Alleghanies did not owe its basin shape primarily 

 to the action of forces concerned in producing the Alleghany 

 Mountains. 



:nox-occueeence of the diamond in xanthophyllite. 



An alleged discovery, some time ago, by Mr. Jeremejew, 

 of minute diamonds in xanthophyllite excited much interest 

 as to the question of the true matrix of this gem ; but the 

 result of recent investigations by Dr. Knop, of Carlsruhe, 

 shows that the so-called crystals are merely angular cavities, 

 shaped like diamonds, it is true, but entirely destitute of any 

 substance whatever. Nor is it probable that they ever con- 

 tained diamonds, since minute sections of xanthophyllite, 

 freshly prepared, and magnified fifteen hundred diameters, 

 appear to be perfectly free from cavities ; but after treating 

 them with sulphuric acid they made their appearance in num- 

 bers, precisely similar to those referred to. In other experi- 

 ments, fine plates of xanthophyllite were examined under a 

 microscope, in all directions, without revealing any peculiar- 

 ity ; but on touching them with a few drops of concentrated 

 sulphuric acid, and heating them until white fumes appeared, 

 the cavities manifested themselves. It is thought, therefore, 

 that this phenomenon is due entirely to the corrosive action 

 of acid on the mineral. 15 A, April, 1873, 265. 



