626 - GEOLOGY OF OHIO. 
As in the case of the preceding quarry, the thickness of the stratum 
of the gray building stone is as yet undetermined. It occurs in courses 
from 3 to 6 inches thick. The upper 3 feet of stone, which is used for 
the purpose of macadamizing, is extracted with neither profit nor loss. 
The material is a more or less porous dolomite of a gray color, mottled 
and streaked with black, which is due to the arrangement of the bitu- 
minous substances contained in the stone. Of the two specimens sent to 
the National Museum, one was polished upon a surface parallel with the 
stratification, and this treatment developed a beautiful structure, due to 
the presence of a fossil bryozoan, which filled the layer that was cut. 
Thus the presence of a fossil in abundance was demonstrated, although 
the rough stone gave no indication of a fossiliferous character. This 
stone and the one previously described from Lima are the only stones 
of a fossiliferous character which were sent to the Museum, and which 
were obtained from the Helderberg formation. 
These stones are thus most markedly contrasted with those from 
the Niagara, which are almost all fossiliferous, as is indicated by micro- 
scopic examination, which very often renders the forms evident when 
they are invisible to the naked eye. 
In the eastern part of the township of Bluffton the quarries are 
better adapted to supplying flagging than building stone, since the 
thickness of the strata usually varies from 1 inch to 3 inches. When 
properly laid down these slabs make a very durable paving material for 
sidewalks, cellar bottoms, ete. They are very hard, but break quite easily 
into any required shape. ‘The stone is dark-colored and of the same 
character as those previously described. Its color is imparted to it by 
bituminous substances, and the dark streaks with which it is filled are 
very irregular, so that a pattern not at all unattractive to the eye is 
developed upon the smooth or polished surfaces of the blocks, and when 
dressed in the usual way and laid with white mortar they make a beau- 
tiful wall for smaller buildings. Such large blocks have been moved as 
to insure the possibility of obtaining blocks as large as might be desired. 
Although the quarries described have been recently opened, the 
stone has been quarried in the immediate neighborhood for fifteen years. 
Scott’s Crossing is situated 4 miles east of Delphos, on the Pitts- 
burgh, Fort Wayne, and Chicago railroad. A quarry at this place 
produced a drab-colored limestone, which occurs in courses from 3 to 
11 inches thick, and which serves very well for foundations. Samples 
