No. 275.] 
333 
soft gypseous mar). In iLe southern counties they are in more profusion 
than in the limestone districts, thus proving the alluvial origin of marl 
in these places; for if it resulted from the decomposition of limestone 
in place, it would be found in those regions most abundantly; which 
is not so. The alluvium contains a large quantity of calcareous matter, 
as is evidenced by the gravel being cemented by it in many places, form- 
ing a coarse conglomerate; and in others, the pebbles are covered with 
a deposit of the same material. The percolation of water through 
these immense piles of alluvium results in the solution, and afterwards 
the deposition of the calcareous particles; forming when deposited un- 
der water the fine pulverulent lake marl, and when exposed to the at- 
mosphere, the porous substance called tufa. 
In many places where these materials exist in abundance, limestone 
is brought from a great distance and burned for lime, while the marl, 
which is equal if not superior, remains in the bog. Thus at points dis- 
tant from limestone quarries, the cost of lime greatly exceeds that for 
which it might be obtained from materials on the spot. I am not able 
to state the exact amount in loads or bushels, but am quite sure that 
the deposits of marl in the southern counties, are sufficient to supply 
the demand for lime and other purposes for an indefinite period. 
There are several localities of marl in Seneca county; one of these 
is in the north part of Varick, about a mile from the lake shore. 
Near the village of Ovid, on Mr. Dunlap's farm, are several beds of 
marl; one of them, covering four or five acres, has been penetrated four 
feet, below which point it becomes sandy. It has been used both for 
lime and for agricultural purposes, in its present state. For the latter 
Mr. Dunlap considers it very beneficial; and a dressing of marl produces 
perceptible effects on the crops for many years afterwards. The marl 
at this place is a deposit from springs which have their source near the 
summit of the hill east. 
The Cayuga maxshesj embracing an area of forty thousand acres, are 
in many, and probably all, places underlaid by marl to the depth of se- 
veral feet. This immense deposit contains far more than all known in 
the fourth district besides; and when the marshes are drained, as boubt- 
less they will be eventually, this material will furnish lime and manure 
for an extensive district of country. 
Some notice of the attempt to drain these marshes, was given in the 
report of last year; but so long as the lakes retain their present eleva- 
tion, and are subjected to annual floods, such a plan, as the one pro- 
