1884.] -LSJ [Stevenson. 



garded as undetermined. Fossils may be present and may have been over- 

 looked by tlie workmen ; examinations by geologists have been of the 

 most casual sort, so that the statements respecting absence of fossils are 

 necessarily of no positive value. Capellini's studies in the Tuscan de- 

 posits, as well as elsewhere in Italy, bear this statement out ; for after the 

 gypsum and its associated marls had been pronounced non-fossiliferous by 

 many geologists, an extensive fauna was discovered, which he has de^ 

 scribed and illustrated in his numerous memoirs. 



Origin of these Deposits. 



So long as these deposits could be regarded as of Lower Carboniferous 

 or Cambro-Silurian age, there seemed to be little difBculty in accounting 

 for them as beds of limestone changed by the action of acid springs or as 

 beds of gypsum actually deposited as such from the ocean waters. Im- 

 probable as the former explanation might appear in this region where sul- 

 phurous springs issue in many places from limestone without having any 

 gypsum in the vicinity, yet it is altogether possible, for Capellini* tells of 

 instances near Cervaro in Naples, where, by the action of hot sulphur 

 springs, nummulitic limestone has been converted from crystalline into fib- 

 rous gypsum, containing sandy veins and semi-opal derived from silica of 

 the nummulites. Occasional masses of unchanged limestone were seen 

 there, doubtless owing their preservation to some difference in composi- 

 tion. 



The other method of accounting for the beds is even more readily to be 

 received. Newberry has shown for a part at least of the Salinaf gypsif- 

 erous deposits that the gypsum was most probably deposited as such in 

 lagoons, and the writer has described beds of saccharoidal % gypsum de- 

 posited as such in the Carboniferous and Triassic of Colorado. 



But this deposit belongs not to any regularly bedded series, so that some 

 other explanation must be sought. Any suggestion of deposit from sea- 

 water must be set aside at once for the deposit is fully 1700 feet above tide 

 and there is practically no bitterwater in the brine at Sallville. We have 

 to explain the occurrence of gypsum, rocksalt, red marly clay ; the gypsum 

 occurring in great amygdules at 1700 feet above tide, in the vicinity of a 

 great fault, and with many sulphur springs still active in the region. 



The general mode of occurrence is very like that of the Permian de- 

 posits near Recoaro in Venice, as described by Taramelli.§ 



The gypsum is in amygdules of great size, accompanied by pale sandy 

 marl, looking like volcanic ash, but distinctly calcareous. Capellini || in his 



*Capellini. Ariano e dintorni. Cenni Geologici sulle Valle dell' Uflta, etc. 

 Mem. deir Acead. di Bologna, 1869, pp. 15 et seq. 



t Newberry. Report of the Geological Survey of Ohio, Vol. ii, p. 191. 



JStevenson. U. S. Explorations west of the 100th Merid., Vol. iii, pp. 364, 379, 

 380. 



g Taramelli. Geologia delle Provincle Venete, 1882, pp. 69 et seq. 



|[ Capellini. La Formazione Gessosa di Castellina Marittima. Mem. Accad. 

 Sci. di Bologna, 1874, pp. 16 et seq. 



