No. 200.] 
367 
Tufa^ Marl^ or materials for Agriculture. 
Tufa is found in small quantities in many places, particularly along 
the north slope of the mountain ridge, but it nowhere occurs in such 
abundance as in Monroe county. 
Shell marl is found in swamps between the mountain and the lake 
ridges. An extensive deposit of this substance occurs in a swamp five 
miles east of Lockport. It has been used at this place as a substitute 
for lime, but not as a manure. Several other swamps of similar charac- 
ter occur on the south side of the ridge road. In the south part of the 
county, along the Tonnewanda creek, are found beds of marl, but the 
condition of the country will not admit of accurate examinations. These 
beds being in low grounds, they cannot be available till the land is 
drained. 
The lower part of the gypseous rocks extend into Niagara county, 
and where they approach the surface, can be used to great advantage on 
sandy soils. 
The partially decomposed calcareous shales on the northern slope of 
the mountain ridge, are a good material for manures on sandy lands; but 
the large proportion of argillaceous matter precludes their use where 
there is already sufficient clay in the soil. 
Bog ore can be obtained on almost every farm north of the ridge, and 
would be of great advantage if pulverized and spread over the surface. 
Metals, 
Bog iron is the only metallic ore of any importance, and this is not 
found in sufficient abundance for manufacturing. It occurs in beds a 
few inches thick in many places in the northern part of the county, per- 
haps none more than six or eight inches thick. I collected specimens 
from Lewiston, and from the farm of Deacon Holmes, in Wilson. In 
both places the deposit covers a considerable extent of surface, but is of 
little depth. The rocks from which this ore is derived are shale and 
sandstone, and the proportion of iron in these is so small that large de- 
posits are not made. 
The argillaceous iron ore of Wayne and Monroe counties is not any 
where found in Niagara. 
Blende (sulphuret of zinc) is found in cavities of the geodiferous 
limestone, at Lockport, and at Niagara Falls, and sometimes dissemi- 
nated in the rock. The quantity is only sufficient for cabinet speci- 
mens. 
