360 CHARLES S. PROSSER 



northeast of Duncanville and 7I miles northeast of West Union, 

 Adams County, is given for comparison with that of the "mottled 

 zone:" 



It will be seen from these analyses that the West Union is a 

 much more silicious rock than the "mottled zone" and that the 

 latter is a dolomite. It is to be noted that the chemical composi- 

 tion and lithologic character of the "mottled zone" differ consider- 

 ably from those of the W r est Union limestone in its typical region. 



The rock between the first and second cap rocks of the quarry- 

 men is called by them the "buff building stone" and corresponds 

 to Zones 15 and 16 of the last-given section, all of which evidently 

 belongs in the Springfield dolomite. 



All the rock above the shale zone (No. n) of the Osgood beds 

 is quarried and crushed for concrete and road material. The fine 

 rock, which the men call ''sand," binds well on the roads, and it was 

 stated that the entire product of the quarry for 1914 was used on 

 tin- Ohio roads by the State Highway Commissioner. 



Dr. Foerste some years ago published a brief description of the 

 Weaver quarries, located on the northern side of Twin Creek, oppo- 

 site the eastern part of the Lewisburg Stone Co. quarry. 1 Recently 

 Professor Bownocker has published a section of the Lewisburg 

 quarry in which the upper limestone of the Osgood beds with a 

 thickness of 9 feet 1 1 inches corresponds to the Laurel limestone of 

 the last-given section. 2 The 3 feet of blue clay beneath is the 

 Osgood shale and the subjacent 10 feet of "blue-gray limestone" 

 the Dayton. The "West Union limestone," 4§ feet thick, 3 corre- 

 sponds to the "mottled zone" of the last-given section, overlying 

 which is the Springfield with a thickness of 8 feet and then the 

 Cedarville which forms the highest part of the quarry. Apparently 

 the line of division between the Springfield and Cedarville dolomites 



1 Journal of the Cincinnati Society of Natural History, XYIII (1896), 183, 184. 

 'Geological Survey of Ohio, 4th Ser., Bull. iS (1915), p. 40. 

 * Ibid., p, 



