STONE. 
Several brief papers on building stone are here presented. During 
the last year other extensive investigations in various important 
quarry districts have been commenced by the Survey, the results of 
which are not yet in form for publication here. The slate industry 
has been given particular attention, reports being published or in 
preparation on the slates of Vermont, New York, Pennsylvania, 
West Virginia, and Georgia. 
THE STONE INDUSTRY IN THE VICINITY OF CHICAGO, ILL." 
Bv William C. Alden. 
LIMESTONE. 
The supply of limestone within the Chicago district, so exposed or 
so thinly covered as to be easity reached, seems to be quite adequate 
to the demand; at least, not all the exposures are utilized for the pro- 
duction of the commodity. The exposures are so distributed as to be 
convenient to Chicago and its nearest suburbs, but the country dis- 
tricts lying in the morainal track are not so well supplied. 
BUILDING STONE. 
The strata considered by Dr. Bannister as the lower division of the 
Niagara group afford one of the best building stones in the State. 
These are exposed on the floor of Desplaines Valley northeast of 
Lemont. The location, being formerly known as Athens, gave the 
name "Athens marble" to the rock, by which name it is known wher- 
ever used. The same beds are seen in the western end of the Sag, at 
its junction with Desplaines Valley. The rock at the Western Stone 
Companj^'s quarries, Lemont, is a fine-grained, even-textured lime- 
stone, of an agreeable light-drab color when first taken from the 
quarry. On exposure to the air the color changes to a buff or yellow. 
The rock rubs well, though not capable of receiving a very fine polish. 
a Abstract from Geologic Atlas U. S., folio 81, Chicago. 
357 
