1891. | FAIRCHILD—SECTION OF STRATA AT ROCHESTER.., 183 
These directions were followed, after the first samples, as carefully, 
it is believed, as could conveniently be done by the drillers. There is, 
of course, a range of error of a few feet. The record obtained is of 
special value because the section includes all the strata from the 
Niagara to the Calciferous or, possibly, to the Archean ; because of 
the care with which it was made; and also because samples of the boring 
will be preserved in the Museum of the University of Rochester, and 
duplicates in the National Museum at Washington, and in the museum 
of Cornell University. 
In the neighboring ravine of the Genesee, about one mile distant 
from the well, the strata of the Niagara Period are shown as far down 
as one hundred feet into the red Medina, which enables us to check off 
the first few measurements of the well record. The first sample was 
taken at the top of the rock-section, in the Niagara limestone, and 
covers 156 feet, the second sample being taken 156 feet lower and rep- 
resenting the upper Clinton shale. 
The following table shows the correspondence between the exposed 
strata and-the first part of the record. 
THICKNESS SHOWN 
WELL RECORD. 
IN GENESEE RAVINE. 
Sample. Strata. Thickness. 
Drift. Se Tee 
1 Niagara limestone. } Gor teeta 
Niagara shale. ‘3 156 feet. soe" =: 
Clinton limestone. | Bor «MS 
Clinton upper green shale. aad Cy ie 
3 Clinton (Pentamerous) limestone. 15 “ WA petees 
4 Clinton lower green shale. aa BAN Se 
Medina gray band. (not noted) ae 
5 Red Medina sandstone. + - 
The discrepancy shown above in the measurement of the Lower 
Clinton shale may be due to counting in the top of the Medina, or, 
possibly to a thickening of the shale in the direction of the well. The 
whole table indicates more accurate observation and measurement than 
is usual in well records. 
