108 GEOLOGY OF THE THIRD DISTRICT. 



Stone, and in some others in the third district, but less distinctly. As their origin is due to 

 sulphate of magnesia, for the sake of brevity they might be termed epsomites. The carbon 

 which usually lines the cavities, shows that tlic liquid which held the salt in solution con- 

 tained bituminous matter, the salt ejecting its particles in the act of assuming form, as wc 

 find in the purification of acetic acid when obtained from the distillation of wood. It is highly 

 probable that the brown color, so common to some of the gypseous masses, may be due to 

 bituminous matter. 



The cavities or epsomites are found in the western country in greater length than in New- 

 York, having met with some in Kentucky which were over six inches long. Dr. Locke, 

 in the American Journal of Science and Arts for January, 1842, has given a description and 

 a drawing of some beautiful forms discovered in the Mammoth cave of Kentucky, which 

 doubtless would be ascribed to epsom salts, were their material not gypsum, which is white 

 and semi-transparent, from whence in part their beauty. In several localities in New- York, 

 the cavities are filled with wliite crystalline carbonate of lime ; and they have also been seen 

 with the curl which takes place when the action is too great on one side, of which there are 

 specimens in the collection, requiring but the removal of their matrix to correspond in all 

 essentials but composition with those of the Great cave. In the Report of 1838, the fact of 

 the appearance of epsom salts upon a specimen from the falls of Niagara, was significant of 

 their origin ; and the occurrence of the same salt in the cave where those described by Dr. 

 Locke were found, would show a like connection and like origin, were it not for their com- 

 position, and that the fibrous form is one of the common ones of gypsum. Should the forms 

 in the cave be the result of an original action or crystallization of gypsum, and not of a sub- 

 stitution of gypseous particles for those of sulphate of magnesia, either of composition which 

 took place in the cavities, or otherwise, then two causes of their production will be known ; 

 and some character must be discovered to distinguish the one kind from the other, if deemed 

 important. These cavities and forms are analogous to those beautiful productions of frost 

 often seen in wet and loose soil, when a sudden and considerable fall of temperature takes 

 place, producing a rapid crystallization. 



The degree of dip of the group at Syracuse, being an object of practical importance, was 

 in a measure ascertained by a level kindly undertaken by Mr. Hutchinson, formerly engineer 

 of that section of the canal. The points chosen for the purpose, were the hill at Salina vil- 

 lage where the porous rock appears ; and that part of the road to Onondaga hollow, where the 

 same rock also shows itself by the road side : The height of the first point above Onondaga 

 lake was 108.04 feet, and that of the latter 34.10 feet, the distance being 2.51 miles from 

 each other, making the dip about 25 i feet to the mile ; which nearly accords with a measure- 

 ment of dip of ihe corniferous limestone in Oneida county, which was 27 feet in the same 

 distance. The direction between the two points in Onondaga being S. 15° W., and not S.W., 

 which is nearer the direction of the group, makes the observed dip rather less than the real one. 



The group, as a whole, presents the same order of saline deposits, including iron, obser- 

 vable in the salt-pans where solar evaporation is used. The first deposit in the pans is ferru- 

 ginous, being red oxide of iron, and staining of a red color whatever it falls upon ; the next 



