ONONDAGA COUNTY. 279 



feet, is as yet unproductive of any valuable mineral. The greater part of the surface portion 

 of Onondaga lake is excavated in the red shale, the lower part of the whole of it extending 

 considerably into its mass. Such also must be the case with Sodom lake, from its depth of 

 one hundred and sixty-eight feet. 



The space occupied by the gypseous portion of the deposit, is from about three to four 

 miles broad ; the villages of Hartsville, Fayetteville, Onrille, Camillus and Elbridge being 

 placed near the line of its centre. Within the space containing the gypseous masses, we find 

 the whole of the porous or vermicular limestone, the salt cavities or hoppers, and the fibrous 

 cavities caused by sulphate of magnesia. Very little gypsum is quarried at the west end of the 

 coimty, the quarries being opened chiefly in the towns of Manlius and De Witt ; not that the 

 west part is not productive in this mineral, the grading of the railroad along Nine-mile creek 

 proving it to be equally if not more so than the east end. From the great size of the masses 

 upon Cayuga lake near Springport, the quantity of gypsum is either greater west, which no 

 fact noticed in the fourth district proves ; or what is more probable, the maximum quantity 

 is to the south of its northern outcrop. Should such be the case, from the association of rock 

 salt with gypsum, any boring for the former, independent of the facts heretofore made known, 

 should be south, and in accordance with the range of the greatest deposit of. plaster. 



The porous or vermicular limestone is greatest in amount in this district, forming two 

 distinct deposits : the upper, which is the same with that in Madison county, the average 

 thickness of which is about four feet. In that county it appears to be continuous as to mass, 

 •as well as holding the same position. In Onondaga, no attempt was made to ascertain if it is 

 continuous or not ; but its position is fixed, being placed above the first series of plaster masses, 

 and above the hopper cavities. It is well exposed in the hill at the Foot-street road near 

 Syracuse, and also on the road which leads from the turnpike to Bellisle ; but better on Nine- 

 mile creek, between the tvumpike and the embankment, in the hill-side above the raihroad. 

 The pores of the upper mass are generally large, though also small ; in which latter case, 

 they are not to be distinguished from those of the lower, the material being the same in com- 

 position and color. 



The lower mass, at the two localities where it is best exhibited, is about twenty feet thick, 

 its pores small and color brown, though it is likely that this color in both masses is the eflfect 

 of alteration, its porous nature readily admitting of a change even though not exposed to the 

 surface, and its original color appearing to have been a dark blue. On the road from the 

 turnpike to Bellisle, the interposed masses to the two porous rocks are similar to those below 

 the upper one in Madison, and contains also the same fossil shells as at Bull's quarry. 



At Syracuse, in the Foot-street road, the thickness of the lower porous rock is about the 

 same ; some of the intervening parts are also of the same kind with those of the former loca- 

 lities, but with other products having a crystalline character, being serpentines ; the action of 

 crystallization having operated powerfully, though locally, producing mica and even nodules 

 of granite, or rather sienite. It is not necessary to suppose that any great degree of heat has 

 here existed to produce these bodies ; nothing more being required, than that their elements 



