204 RECORD OF DEEP-WELL DRILLING FOR 1905. 
282. Well at Galewood, Cook County. 
[Well completed in 1905. Authority, Chicago, Milwaukee and St. Paul Railway, owner. No samples. 
Geologic correlations checked by G. H. Ashley.] 
This record is of interest in connection with that of well No. 280, from its greater depth. 
It agrees with others from near Chicago. The formations, in downward order, are Niagara 
limestone (Silurian); Cincinnati shale, Galena and Trenton limestones; St. Peter sandstone, 
and ''Lower Magnesian" limestone (Ordovician); Madison sandstone, Mendota limestone, 
and Potsdam sandstone (Cambrian). 
Record of well at Galewood. 
Feet. 
Drift 0- 94 
Niagara: 
Limestone 94- 26£ 
Cincinnati : 
Shale 265- 5W| 
Galena and Trenton: 
Limestone - 505- 84i 4fj 
St. Peter, in part: 
Sandstone 845- 92, 
"Lower Magnesian : " 
Limestone; caves from 1,160 to 1,264 feet, containing crevices; also 
streaks of shale 925-1, 32, 
Madison (?): 
Sandstone 1 , 325-1, 52 ] 
Mendota (?): 
Hard limestone 1, 525-1, 54">l 
Streaky shale 1, 540-1, 62i|| 
Shale 1, 620-1 , 64 i 
Limestone 1, 64.5-1 , 7£ j 
Potsdam: 
Sandstone 1, 785-1, 8( J 
Limestone 1, 804-1, 8: | 
Shale 1 , 812-1 , 8 c 
Sandstone 1, 81.5-1 , 8 ! 
Diameter of well, 101, 8, 6, and 5 inches. Water stands 84 feet below surface. 
384. Well in T. 7, K. 12, Crawford County. 
[Authority, John F. Lafferty. No samples.] 
This record shows the general character of the formations penetrated by the gas and 
wells in the southern part of the Illinois field. The formations are part of the Carb( i 
iferous system and much the greater portion of them are included in the Pennsylvanian J 
Coal Measures series. The sandstones at 1,134-1,196 feet may be the basal sandstoi : 
of the series, corresponding to the Mansfield sandstone of the Indiana geologists. 
Record of well in sec. 28, T. 7, R. 12. 
J Feet. 
Clay and shale 0- 
Sandstone 110- 
Black shale 140- 
Dark slate 1 60- 
Light and dark shale 175- 
Light sandstone 220- 
Light "sticky" shale 228- 
