WATER- LIME GROUP. Ill 



absent, which is usually the case, it makes the whitest hme, and requires less fuel to burn a 

 given measure of it than of any of the other limestone rocks. 



The manner in which this layer is fractured or cracked, shows the absence of clay, the 

 tendency of which is to separate in layers, and that its impurities are siliceous, and that the 

 silex existed in that state in which the tendency to accretion predominated. Even where the 

 sihceous nodules or flint are not visible, there are parts of the layer in certain localities which 

 show themselves as core, after the stone is burnt. 



Along the whole of the outcrop of these upper or Helderberg limestone rocks and groups, 

 wherever this layer appears in the district, if it contains no nodules of flint, it is the one which 

 is burnt for lime ; a circumstance which shows the sagacity of the limeburners. 



In some parts of the west end of the district, some of the layers have abounded in Colum- 

 naria, the species yet undetermined ; their character, generally obliterated ; the space they 

 occupied, in part occupied by flint, which by long exposure, and the removal of the limestone 

 in part, gives to the layers a ragged and uncouth appearance. 



West of Oneida creek, the portion burnt for water-lime consists of two layers of a drab 

 color, which appear to be coextensive with the group. It is dull in its fracture, and com- 

 posed of minute grains, with usually but a few hnes of division. The upper layer is some- 

 what shelly, as it is termed, breaking into irregular thin curved fragments or plates. Less 

 heat is required to burn the upper than the lower layer. Where the two kinds are burnt in 

 the same kiln, the one from the lower layer is placed at the bottom, and the other above it. 

 About sixteen cords of wood are required to bum one thousand bushels of water limestone in 

 the common kilns. 



To those unacquainted with the tests whereby a water-lime is known, the same being now 

 an object of great importance from the many uses to which it may be applied, it may be well 

 to state, that the stone must not slake when burnt ; when ground, it must harden or set when 

 mixed with water ; and when set, it should remain so under water, the goodness depending 

 upon the hardness or cohesion when set. 



The line of separation between the water-lime group, and the Onondaga salt group, is rather 

 well defined at the eastern end of the district. There a brownish impure limestone is seen, 

 often mottled, containing columnariae of a somewhat spherical form, and about the size of an 

 inch or more ; also a few encrinital fragments, and a small orthocera, the species not named. 

 This is the mass which separates the two groups, and forms the base of the water-lime group. 

 At the west end of the district, the opportunities to obtain a knowledge of the intermediate 

 mass are but few and imperfect. The best place is on the road from Jamesville, on the east 

 side of the creek, not far from Dunlop's mill. A number of layers appear of a brownish drab 

 color, some of them containing very white lamellar carbonate of lime in small globular parti- 

 cles. No fossils were seen, but Uttle of the rock being exposed, and therefore no definite 

 result obtained. 



The same columnaria which exists at the base of the group, occurs at the top of the group 

 immediately under the pentamerus hmestone. This is most obvious in the town of Warren, 

 south of Mr. Crugar's, in the road to Richford springs. The columnaria occurs in a brown 



