River VaJlcjis of the Ozark FUifcon. — llcrshcij. 8ol 
embaynient. Litliologically, the deposit under discussion 
bears a strong resemblance to portions f)f the Lafayette for- 
mation where it was laid down in valleys near the coast line 
of the sea in which the main body of the deposit was being- 
formed; and, so far as 1 have been able to learn, the terrace 
deposits of the James and upper White river valleys run {b)wn 
the sides of the latter valley until they connect with the un- 
doubted Lafayette deposits of the embaynient region. 
Assuming our correlation to be correct, we tind that, during 
the period of submergence of the lower Mississippi region and 
deposition of the Lafayette formation, the erosion of the 
Ozarks was in a period of quiescence. The streams meander- 
ed in broad tiood-plains, their power of excavation was at a 
minimum, and they were slowly building up a red loamy de- 
posit, which, as it took place in the Ozarks, could not hel]) 
but have large quantities of gravel incorporated with it, and 
which may be consideretl ;js the Ozark type of the Lafayette 
formation. 
Perhaps the bright red color of the deposits of that period 
indicates a somewhat warmer climate in the Ozarks than at 
present. 
Post-Lafavktte Elevation. 
It is a well known fact that the Lafayette period was 
terminated b}^ an elevation of the continental jjlateau, at 
least in the vicinity of the former areas of deposition; and, 
from the existence of deep submarine continuations of the 
present river valleys, the elevation appears to have been of 
continental extent, and to have terminated the Tertiary era 
and initiated the Quaternary. The Ozark plateau partici- 
pated in this great epeirogenic movement. The lowe^- canons 
or present valleys of tiie streams are a record of this eleva- 
tion, and they also sliow that to a certain extent the elevation 
has been permanent. It may have originally l)een greater 
than now, and during the Columbia epoch w;is undoubtedly 
less than now; but the altitude of the Ozarks relative to that 
of the lands north, east, and south of them, is now greater 
than it was previous to the jiost-I^afayette elevation. That is, 
in adilition to the grand epeirogenic movement, there was 
also a slight f»rogiMiii' iiioxcniciit. such as has fre(|Ucntly 
affected the Ozarks. 
