694 A. F. FOERSTE 



determine the fact that in all essentials the Silurian and Devonian 

 sections of the Wells Creek basin strongly resemble those of the 

 Tennessee River valley. 



E. THE EQUIVALENCE OF THE CLIFTON, LINDEN, AND CAMDEN 

 LIMESTONES TO OTHER BEDS. 



In the Geology of Tett7iessee, published in 1869, Professor Saf- 

 ford included all Niagaran strata, from the Clinton bed to the 

 Brownsport bed, inclusive, in his Meniscus lii^ne stone. He recog- 

 nized, however, two subdivisions, each about 100 feet thick, the 

 lower called the Variegated bed, the upper called the Sponge- 

 bearittg bed. The Variegated bed included the Clinton, Osgood, 

 Laurel, Waldron, and Dixon beds of the present paper. The 

 Sponge-bearing bed included the Brownsport bed. Astraeo- 

 spongia meniscus is confined to the upper or Sponge-bearing bed. 



In the Elementary Geology of Te?i?iessee, published in 1876, 

 Safford and Killebrew proposed the name Clifto?i limesto?ie for the 

 Meniscus limestone. This name is, therefore, equivalent to the 

 name "Niagaran" as now defined. 



At Clifton, the type locality, the section along the river below 

 the landing includes the Clinton, Osgood, and Laurel limestones. 

 The section along the river about three-quarters of a mile above 

 the landing includes the upper part of the Laurel bed, the Wal- 

 dron, Lego, and Dixon beds, and the greater part of the Browns- 

 port bed. Immediately in the rear of the town, on the hillside 

 north of the Waynesboro road, the upper part of the Lego bed, 

 all of the Dixon red clay, and the base of the Brownsport bed are 

 exposed. 



As a synonym for the Niagaran, the name "Clifton lime- 

 stone" will be found useful. 



In the Geology of Temiessee, all strata in western Tennessee 

 intervening between the Clifton bed and the Chattanooga black 

 shale were included in the Lower Helderberg. In 1876, in the 

 Elementary Geology, Safford and Killebrew employed the name 

 Linden limestone for these strata. In 1899 Safford and Shuchert 

 published an article in the American Journal of Science, entitled 

 "The Camden Chert of Tennessee and its Lower Oriskany 



