yo.1621. LATE NIAGARAN STRATA—PATE AND BASSLER. 409 
The name Meniscus limestone is misleading, since the characteriz- 
ing sponge, Astrwospongia meniscus, is found only in the upper or 
sponge-bearing bed. In 1876 this name was changed to the Clifton 
limestone by Safford and Killebrew in their Elementary Geology of 
Tennessee. 
In 1908, Dr. A. F. Foerste * published his valuable paper “ Silurian 
and Devonian Limestones of Western Tennessee,” by far the most 
important contribution to this subject. Doctor Foerste’s studies led 
him to recognize in Safford’s Variegated beds the Clinton, Osgood, 
Laurel, and Waldron formations of the western flank of the Cincin- 
nati geanticline, and at the top of this division two new formations, 
the Lego limestones and Dixon beds. To Safford’s upper member, 
or sponge-bearing bed, as exposed at Clifton and Brownsport Fur- 
nace, Foerste applied the new name Brownsport. Other new names, - 
the Maddox limestone of early Niagaran age, the Glenkirk limestone 
for a combination of the Laurel, Waldron, and Lego, when these 
could not be separated, and the Gant bed for an arenaceous limestone 
phase of a part of these late Niagaran rocks, were instituted. Doc- 
tor Foerste’s article contains much valuable information, but his 
arrangements of facts, particularly in the description of sections, is 
such that it is difficult to assemble his evidence. We are in accord 
with most of Foerste’s work on the lower portion of the Niagaran, 
and our efforts in this paper are to present a detailed account of. the 
late Niagaran, with particular reference to the Brownsport divi- 
sion. We have made free use of Doctor Foerste’s work and wish to 
acknowledge our indebtedness to his publication. 
‘A study of the stratigraphy of this general area has shown numer- 
ous unconformities in strata which are essentially horizontal. The 
geologic range 1s from the lowest Trenton to the Mississippian, but 
the main geologic divisions are seldom conformable. The lowest 
Trenton is succeeded by the uppermost Cincinnatian strata; the 
Niagaran rocks are followed by Helderbergian strata of New Scot- 
land age, and even in these larger divisions unconformities are noted 
between their individual members. 
Such minor unconformities are indicated in the table of sections 
on page 428. It may also be noted that, so far as observed, no single 
locality affords a complete and continuous section of all the Niagaran 
strata known to occur in the area. For example, at the type-locality, 
Clifton, in Wayne County, a considerable portion of the late Niag- 
aran is wanting; even at Decaturville, where probably the most com- 
plete section of the entire area may be seen, several members are 
missing. It is, therefore, only by comparing section after section 
that the complete succession may be determined. The composite 
section offered on a subsequent page was thus compiled. 
@ Journal of Geology, XI, pp. 554-715. 
