GEOLOGY OF THE FOURTH DISTRICT. 
Mineral Contents of the Rock. 
Copper and iron pyrites, with oxide of manganese and iron, and carbonate of copper, are 
the only metallic substances I have met with in this rock, and these only in minute quantities. 
At Lewiston the upper part of the mass contains numerous small spiculse of pyritous copper, 
and the fissures and joints are often lined with a thin coating of green carbonate of copper; and 
on subsequent examination, I find that at this locality it is very generally diffused, though the 
quantity is small. 
The hydrated peroxide of iron is seen lining small cavities in the grey quartzose sandstone 
at Lewiston and elsewhere ; and the black oxide of manganese is commonly seen in the joints 
and between the laminae, though never in large quantities. 
A reddish colored sulphate of baryta in small spherical masses, or filling small cavities in 
the rock, occurs at Rochester and a few other places. 
Carburettecl hydrogen gas rises from this rock in considerable abundance in some places 
along the Erie canal east of Lockport. The principal point is Gasport, where it is collected 
and passed through a tube, supplying a quantity sufficient to illuminate a large room constant¬ 
ly. The light is less brilliant than that of artificial gas, being more yellow, and, from the 
manner in which it is consumed, giving rise to much smoke. I have seen no places which 
emit sufficient quantity to induce the erection of apparatus for collecting it, except as a matter 
of curiosity. The evidence of bituminous matter is here fully established, even if the green 
threads and spots were not considered sufficient; but the origin of this is still left in obscurity. 
The amount of organic matter, both animal and vegetable, known in this rock, is so exceed¬ 
ingly small, that it could scarcely be supposed to give rise to the constant emission of this 
gas. The impervious nature of the lower part of the mass, and the absence of fossils in the 
next rock below, would preclude the idea of its origin in that direction, as there are no dis¬ 
turbances known in the district. 
Springs. —Along the outcropping edges of the siliceous portions of the mass the soil is 
thin, and water readily percolates through the fissures, offering no springs. The more even 
surfaces, particularly of the lower division, are sufficiently moist, and in level situations or 
depressions too much so, for fertility. Springs are of frequent occurrence at the junction of 
the Second division with the more impervious mass below. 
Saline springs are everywhere to be found in this rock throughout its whole extent, from 
the eastern part of Wayne county, and even as far as Oswego, to the Niagara river; and 
beyond this, in Canada, deep borings have been made and much salt water obtained. In 
some places salt had been manufactured, for a long time previous to opening the Erie canal; 
but the greater facilities and better quality of the brine at. Salina, with that means of transpor¬ 
tation, soon superseded the manufacture of salt from any of the springs in this rock. It ap¬ 
pears in all cases where I have been able to obtain any knowledge upon the subject, that there 
is a large admixture of impurity in the brine, and the salt has a “ sharp bitter taste ” and brown 
