No. 200.] 
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bricks has been limited to a few points. As many as five or six beds 
of clay have been wrought in the vicinity of Rochester, from Avhich 
about 2,000,000 of bricks are furnished annually. Bricks have been 
made near the village of North Penfield, and there is an extensive depo- 
sit of clay on the lake shore in the north part of the town of Brighton. 
Bricks are made near Fairport and at Mendon and Pittsford. Beds of 
clay occur near Clarkson and Brockport; from some of which bricks 
have been made. We might enumerate every town in the county, but 
the materials are similar and are found in all. 
Clays might be used, to manifest advantage, on some of the sandy 
soils, particularly in the eastern part of the county, where the same 
farm often contains both sand and clay. 
The decomposing gypseous marls appear at the surface in Pittsford, 
and other places, where they have been mistaken for clay. This marl 
contains too much carbonate of lime to be useful for bricks, but would 
be valuable if used as a manure on sandy lands. It makes bricks of a 
very inferior quality, which crumble on exposure to rains, and are pecu- 
liarly unfit for exposure to water. 
- Sands. 
The only pure siliceous sands we find in this county are on the lake 
shore. With these garnet and iron sands occur in small quantities. — 
Coarse sand or fine gravel, fit for making mortar, is found in many 
places, particularly along the Irondequoit, antl in many of the dilu- 
vial hills. The fine sand of the diluvial hills contains too much alu- 
minous matter to be useful where a siliceous sand is required. At liie 
outlet of the Irondequoit bay great quantities of a pure siliceous sand 
is drifted into ridges along the shore. Sand may be obtained from 
this place, in sufliicient quantities for the manufacture of glass, or for 
sawing marble, should it ever be required for such purpose. This kind 
of sand is found at intervals, and in great quantities along the lake shore 
from the Irondequoit to Sandy creek. Magnetic iron sand and garnet 
sand are also found in considerable quantities, and collected for writing- 
sand. The iron is not in sufficient abundance to be of importance as 
an iron ore. These two sands result from the destruction of granitic 
rocks containing both iron and garnet. 
Water and Springs. 
All the water of the county, and indeed of the whole district, contains 
muriate of lime, being what is termed hard water. The county gene- 
rally is well watered, though in some parts water is not so readily ob- 
