266 
except at Lofton, Rutherford County, where the upper ten feet of the Mur- 
freesboro is absent. 
Ridley limestone. This limestone was named by Safford’ in 1869 from 
the exposure at Ridley’s Mills (now Davis’ mill) near Jefferson, Tennessee. 
Only the lower thirty feet of the formation are exposed at this locality. 
The Ridley limestone has a much wider surface distribution than the older 
formations of the Stones River group. It accurs in Rutherford, Wilson, 
Bedford, Marshall, Williamson, and Davidson counties. Its thickness 
varies from 95 to 120 feet. 
The formation consists of massive, dense, light blue, bituminous lime- 
stone with considerable chert, appearing upon the weathered surfaces. 
These characters are much like those of the Murfreesboro limestone, and 
it is not surprising that Safford confused the formations lithologically. 
The faunas, however, are decidedly different, but in many outcrops 
fossils do not occur and correlation is uncertain except where the contaets 
with either the Pierce or the Lebanon are seen. 
The Ridley limestone is in most places apparently conformable upon 
the Pierce, except near Jefferson, Rutherford County, where the contact is 
slightly undulating. The small variation in thickness of the Pierce lime- 
stone does not indicate a prolonged period of erosion. The following are 
among the most characteristic and abundant fossils: Camerella varians, 
Hebertella bellarugosa, Gonioceras anceps, Orbignyella sublamellosa, Lio- 
spira convera, Protorhyncha ridleyana and Stromatocerium rugosum, 
Lebanon formation. This formation was called the “glade limestone” 
by Safford in 1869’, since it is the surface rock beneath the extensive “cedar 
glades” of central Tennessee. In 1900 Safford and Killebrew? changed the 
name to “Lebanon limestone” presumably from the splendid outcrops of 
the formation in the town of Lebanon, Wilson County. The thickness meas- 
ured by Safford’ near Readyville, Rutherford County, is 118 feet. Other 
measurements in other localities show a variation from 80 to 120 feet. 
The outcrops of this limestone extend over a considerable area in Ruth- 
erford, Wilson, Cannon, Bedford, Marshall, Maury, Williamson, and David- 
son counties, and almost everywhere valuable cedars grow in the shallow 
Lebanon soil. The formation consists of thin layers of dense, light blue, 
fossiliferous limestone separated by seams of shale. In some sections a 
massive coarsely crystalline unfossiliferous bed of limestone occurs near the 
base. Ripple-, rill- and wave-marks are common in different parts of the 
formation, indicating that shallow water conditions prevailed at different 
times during the deposition of the beds. 
Some layers of the formation are made up almost wholly of a single 
species of Plectambonites as seen two miles south of Murfreesboro. Other 
abundant and characteristic fossils are: Scenidium anthonense, Batostoma 
libana, Escharopora briareus, Phragmolites grandis, and Zygospira saffordi. 
The Lebanon lies with apparent conformity upon the Ridley. 
1Geol. Tenn. (1869), p. 261. 
1Geol. Tenn. (1869), p. 258. 
2Blem. Geol. Tenn. (1900), p. 125. 
®Geol. Tenn. (1869), p. 263. 
