334 [Assembly 
tained. Along the northern slope of the " mountain ridge," and over 
the whole of the sandstone formation, water is abundant, either rising to 
the surface in springs, or collecting in the low grounds and forming 
small streams. In digging wells, where the sandstone approaches the 
surface, it is often necessary to penetrate the rock a few feet before a 
constant supply of water is found. After ascending to the top of the 
limestone, water is not so abundant. Few springs rise to the surface, 
and the water accumulating in the low gTOunds and forming small 
streams, is dried up in summer or lost in the fissures of the rock. Con- 
sequently, at such seasons the supply of water on the surface is very li- 
mited. Water is obtained by digging, at different depths; sometimes 
at the surface of the limestone, but commonly by penetrating it a few 
feet. Sometimes in digging wells the limestone is penetrated thirty or 
forty feet. In these cases it is usual to find a cavity or fissure in 
the rock, which affords an abundant supply. The water from the wells 
never overflows the surface, though from the dip of the rocks it might 
probably be made to do so. The water all flows into wells from the 
north, as we would expect from the dip of the strata, and in some cases 
a well dug to the south of one already supplying water, will drain the 
latter entirely. In such cases, it is only necessary to excavate the 
northern well deeper to obtain a supply. 
The southern part of the county is plentifully supplied with water, 
both from springs and streams, though towards the northern limit of the 
gypseous marls it is often necessary to penetrate these rocks to the depth 
of fifty or sixty feet, and in some instances to two hundred and even 
three hundred feet, before a supply is obtained. The earthy or compact 
portions of these rocks affords but little water, till penetrated to consi- 
derable depths; and when it is obtained it appears to flow from a cavity 
or reservoir in the rock. As the rock consists of alternations of shale and 
compact marl, it is often necessray to penetrate, first a thick stratum of 
the marl and then one of the slate, and when we come again to the com- 
pact marl the water is obtained. The latter stratum in these cases is im- 
pervious to water, while it readily percolates through the slaty portion. 
Springs of h} dro-sulphuretted water are of frequent occurrence in al- 
most every part of the county, but more particularly along that portion 
occupied by the' shales, both above and below the limestone. Some of 
these springs are celebrated, and are much resorted to by invalids and 
fashionable visiters. Among these may be enumerated the Monroe 
springs, about five miles from Rochester, pleasantly situated in a grove 
not far from the road leading from Rochester to Pittsford. On this 
