ONONDAGA COUNTY. 277 



bones or teeth of an ancient race of animals, enables us to determine the condition of the sur- 

 face of the earth when they formed a portion of its inhabitants. 



The remaining rocks and groups of Madison county, are the Tully limestone, the Genesee 

 slate and the Ithaca group. These occupy the projecting parts, extending from the southwest 

 part of the county, embracing all Georgetown, all but the northwest and northeast comer of 

 Nelson, the west of Lebanon, the southwest part of Eaton, the southeast portion of Cazenovia, 

 and that part of De Ruyter not covered by the lower group. Beside these, there is also 

 another projection at the southwest of Brookfield. 



The Tully limestone no doubt extends through De Ruyter, from its thickness near the town 

 line, and from its appearance on the turnpike between that village and Smyrna. 



The Genesee slate underlies the village of De Ruyter, appearing in the hill-sides and along 

 the road to Smyrna for some distance, either alone, or with the base of the Ithaca group 

 resting upon it. The shale also appears in its range through Lebanon, &c. &c. 



The Ithaca, including the Portage group, presented but little interest in the county gene- 

 rally. It is a more useful rock than the group below it, because it contains more materials of 

 sandstone for building, but it produces an inferior soil. The most northern part where it was 

 seen, was at Smith's saw-mill, to the east of Nelson's flats, where a mass of about eight feet 

 shows itself, being a light bluish sandstone, which becomes yellow by exposure to the air : it 

 breaks with a curved fracture, the result of a concretionary structure. It rests upon a black 

 shale or slate. Very little rock is exposed upon the side-hill, the surface between there and 

 Peterboro' being apparently not very elevated, and its outhnes having the form of alternate 

 depressions and swells. A rather better exposition is on the road from Cazenovia to New- 

 Woodstock, near the mill-dam on the creek. It shows thin layers of sandstone, straight and 

 waved, with slate and shale, and a few fossils. 



The hill-side below Woodstock, on the road to De Ruyter, shows a gravel plane, which 

 inclines south, rising about one hundred feet above the road, and plainly exhibiting at that 

 level an ancient water-course. It continues from hill to hill, for some distance maintaining 

 about the same elevation above the valley. 



jLbout a mile and a quarter to the south of east of the village of De Ruyter, is Burdick 

 quarry, from whence stone was taken for the academy. It is near the top of the hill, and 

 appertains to the Ithaca group. The Curtain-like and the Retort-shaped fucoids were found 

 in this quarry, as has been before stated and figured. 



8. Onondaga CouNtv. 



This is the most valuable coimty of the district for the products of its subsoil, such as sah, 

 gypsum, water-lime, limestone, etc. Its rocks range east and west, the order of succes- 

 sion being well observed ; one rising upon the other, the lowest being at the north end of the 

 county, and the highest and newest at the south end. The county is very nearly divided by 

 the limestone ridge ; the greater part of the northern half forming a part of the Great level, 



