ONONDAGA SALT GROUP. 99 



The great mass of the deposit, consists of rather soft yellowish or drab and brownish 

 colored shale and slate, both argillaceous and calcareous, and of argillaceous and calcareous 

 slaty and more compact masses which are hard, a brownish color predominating. The 

 whole is usually denominated gypseous marl ; being earthy and indurated, slaty and compact. 

 Some of the indurated and more solid kind, when weathered, presents a peculiar appearance 

 like that of having been hacked by a cutting instrument, and with some regularity ; owing 

 to cracks or joints in two directions, giving a rhombic surface ; which by solution and wear 

 taking place at the cracks, and those not being continuous or regular as to distance, the ap- 

 pearance mentioned is produced. The stone readily breaks in the direction of the furrows or 

 hacks, and the fracture shows stains or marks of infiltration. 



When an acid is applied to the different associates of the gypsum, they do not effervesce 

 in the free manner of purer limestone, but the effect is produced when in powder. It is 

 highly probable that the greater number contain magnesia, which may cause the difference. 

 This earth was found in considerable amount by Dr. Beck, in the upper part of the mass 

 which encloses the lower range of plaster beds, on Nine-mile creek. Its presence is obvious 

 from the serpentine near Syracuse, and from the cavities caused by the removal of epsom 

 salts, which are numerous sbove the gjrpsum in several localities. 



The dark color of the gypsum, and the brownish color of many of its associates, appear 

 to be owing to carbonaceous matter, and not to metallic oxides, becoming lighter by long 

 exposure. The greenish colored shale, so abundant usually in gypseous deposits, appears 

 to be but an inconsiderable portion in the district ; owing to the dark color of its gypsum, 

 and but few parts of the mass having recently been uncovered, and its ready change of 

 color by the action of the weather. 



At the east end of the district, the third deposit crops out of the hill-side to the north of Cherry- 

 Valley village, as may be seen upon the road which leads to the Mohawk. The best place 

 to examine it, is where the sulphur springs issue, and in the ravine to the west of the springs 

 and the road. The lower mass is the thickest ; it is of a yellow or drab color, earthy, soft, 

 calcareous, divisions not well defined, often with irregular cavities lined with minute crystals 

 of carbonate of lime, or partially filled with the same. The mass exposed has evidently 

 changed color. The sulphur springs flow from this mass ; above it is a more solid deposit, 

 in thin layers, straight and striped like ribbons, bluish when fresh, changing gradually to a 

 light brownish color, which finally the whole mass assumes. As the change first takes place 

 at the lines of division, it gives a striped appearance to the mass. These two masses appear, 

 with more or less variation, to be coextensive with the district. No fossils were seen in either 

 at the east end, excepting a few indistinct fucoids ; but the upper mass is the position of the 

 Eurypterus remipes, which is found to the north of Waterville. Above the upper deposit, 

 there are irregular light-colored layers with Globuliform columnaria and other fossils, which 

 belong to the water-lime group, or to an intermediate one which we do not attempt to esta- 

 blish. In the road and creek at Mr. Schawl's, west of the road which leads south to Rich- 

 ford springs, the two kinds also appear. 



