THE NIAGARAN FORMATIONS OF WESTERN OHIO 365 



limestone which has been called the Laurel in the sections farther 

 east along the Stillwater River. 



Samples of the Laurel limestone were collected at the quarry 

 above Derbyshire Falls and analyzed by Professor Demorest with 

 the following result: 



This analysis shows that the Laurel limestone at Derbyshire Falls 

 is a more silicious one than that at the Lewisburg Stone Co. quarry, 

 which contains but 8.85 of silicious residue. On the other hand, 

 the Lewisburg stone contains a larger percentage of CaC0 3 , where 

 it amounts to 56 per cent of the rock; the other constituents at the 

 two localities do not differ to any marked degree. 



