SECTIONS OF TWO MICHIGAN SALT WELLS 321 
The macroscopic examinations were also checked by this micro- 
scopic study. In addition, each sample was subjected to the 
action of both dilute and concentrated hydrochloric acid, and the 
character of the effervescence confirmed or modified the previous 
SECTION OF WELL 500 FEET FROM EAST LAKE STATION, OF THE 
PLANT OF THE R. G. PETERS SALT CO. 
examinations. 
Depth in Feet 
593 
597 
800 
978 
1,325 
1,400 
T,425 
1,450 
1,475 
1,487 
1,500 
1,595 
1,605 
1,638 
1,645 
1,650 
1,652 
1,656 
1,658 
1,661 
1,680 
1,690 
1,700 
1,762 
1,780 
1,800 
1,810 
1,820 
1,830 
1,850 
1,862 
1,870 
1,880 
1,895 
1,920 
T,Q30 
1,940 
1,964 
Blue calcareous shale 
Calcareous shale 
Calcareous shale 
Limestone 
Limestone 
Limestone 
Limestone 
Limestone 
Limestone 
Calcareous shale 
Limestone 
Limestone 
Limestone 
Limestone containing sponge spicules 
Calcareous shale containing sponge spicules 
Calcareous shale containing sponge spicules 
Calcareous shale containing sponge spicules 
Calcareous shale 
Calcareous shale 
Limestone 
Limestone 
Limestone (rather impure) 
Limestone (very sandy) 
Limestone (very sandy) 
Limestone (very sandy) 
Calcareous sandstone 
Calcareous sandstone 
Limestone 
Limestone 
Limestone 
Limestone 
Limestone 
Limestone 
Limestone 
Limestone 
Silicious and ferruginous limestone 
Silicious and ferruginous limestone 
Shaly limestone 
Difficulty was encountered in determining whether 
some particular samples, especially the finely pulverized samples, 
should be referred to the limestone or to the shale group. For 
example, it was found impossible to say absolutely whether a 
