158 ECONOMICAL MINERALOGY. 



linear sides and irregular conical columns. At the southwestern termination of this extensive 

 deposit, about a mile south of the cavern, there are the tufa petrifactions of six logs, which 

 stand obliquely against a side-hill. They are still very perfect, (not having been often- visited,) 

 retaining the forms of the shelly scales of the bark, the knots, etc.* 



Probably the most noted of the springs which are now under consideration, are those found 

 in the vicinity of Chittenango, in Madison County. At the base of a hill, the rocky strata 

 of which contain a large proportion of carbonate of lime, calcareous deposits and incrustations 

 of various kinds are to be found. These have been formed, and are probably daily in the act 

 of formation, by the agency of the waters which continually percolate through this hill of 

 porous limestone. From this locality, specimens may be obtained of leaves, moss, wood, etc., 

 in all states, from that of the proper vegetable, to that of the hard calcareous substance in 

 which scarcely a trace of vegetable matter can be detected. 



Similar deposits and petrifactions are very frequent in the Cotjnty of Onondaga. At the 

 base of a hill near Syracuse, large masses of tufa are to be seen. More extensive deposits 

 occur in the towns of Marcellus and Camillus ; and here, trunks of trees, and aggregates of 

 leaves and roots, converted into pure carbonate of lime, are not uncommon. 



Calcareous tufa is also foimd in great abundance near the Genesee Falls at Rochester, in 

 Monroe County ; in Cayuga County ; near Ithaca, in Tompkins County ; also near the 

 Falls of Niagara, and in various other places which it is scarcely necessary to particularize. 

 At the Niagara and Genesee falls, large masses of moss are found incrusted with carbonate 

 of lime, evidently caused by the carbonate of lime held in solution by the waters whidi are 

 continually passing over them. These incrustations, therefore, are undoubtedly to be referred 

 to causes now in operation. 



There is a great petrifying spring, and vast beds of tufa, at Caledonia, in Livingston 

 County. The whole neighbourhood of that village is one of the most interesting in the State, 

 and even the fences exhibit rich collections of organic remains.! 



The vicinity of Chittenango probably affords the best opportunity for studying the cir- 

 cumstances attending the conversion of vegetable matter into carbonate of lime ; and for the 

 purpose of arriving at some conclusions with regard to these, I subjected to analysis various 

 portions of the tufa or petrified vegetable matter, together with some of the water which issued 

 from a side-hill, and appeared to be the agent concerned in the petrifying process. 



The petrified wood was found to consist almost entirely of carbonate of lime, with very 

 miaute and variable portions of silica, alumina, and oxide of iron. As I have before remarked, 

 in some specimens not a trace of vegetable matter was discoverable, while in others its pre- 

 sence could be easily detected. It is evident, therefore, that while the structure of the plant 

 remains entire, the vegetable matter, by the petrifying process, is, wholly or in a great mea- 

 svure, replaced by the carbonate of lime. 



From the side-hill at the base of which these specimens of petrified vegetables occur, springs 

 of water every where burst out. The superincumbent rock contains a large proportion of 



* Canal Rocks, page 128. f New-York Review for January, 1839. 



