282 



Dr. John T. Plummer on the 



illustrate our topography, and to exhibit the localities of our dif- 

 ferent formations. 



Fig.l. 



Cliff Rock. 



Geological Formations. — The bed of the river opposite Rich- 

 mond, lies eighty five feet below the level of the plain on which 

 the town stands ; and is formed of the blue fossiliferous lime- 

 stone, (the Trenton limestone of the New York geologists,) which 

 rises in some places nearly to the surface of the soil, and consti- 

 tutes the steep banks of the river. Numerous quarries have been 

 opened for miles along these river escarpments ; and they have 

 furnished most of our building stone, the materials for macadami- 

 zing the national road for several miles east and west of town, 

 the rocks for the masonry of several national bridges, and for 

 much of our lime. From the dimensions given, it is obvious 

 that we have an inexhaustible supply of limestone. 



To the eye, the strata of this formation appear to lie perfectly 

 horizontal ; but from the occurrence of more recent formations 

 to the east and the west of us, with other geological data, there 

 appears to be a gentle dip in those directions, producing a de- 

 clivity sufficiently great to admit of the superposition of the coal 

 strata at the western side of Indiana and the eastern side of Ohio. 

 Agreeably to this, Richmond is placed exactly on an anticlinal 

 line running nearly north and south. The layers of the blue 

 limestone vary from less than an inch to more than a foot in 

 thickness, and some of them furnish fine flagstones. Between 

 some of these strata lie seams of a fine blue uncalcareous clay, 



