56 
IOWA ACADEMY OP SCIENCES. 
and accepts the observations on which the statement is based 
as evidence of a synclinal fold extending from Le Claire to Ana- 
mosa. White’s observations appear to have been made only at 
the two points mentioned. At both places the strata seem to 
be inclined at a high angle. On the assumption that the incli- 
nation of the strata indicates orogenic disturbance, the con- 
clusion that the disturbed beds were parts of the same fold was 
very natural. There is, hov/ever, no fold, nor is there any line 
of disturbance. In the whole Niagara area southwest of the 
line which marks the limit of the Le Claire limestone the phe- 
nomena seen at Le Claire and west of Anamosa are repeated 
scores of times and in ways that defy systematic arrangement.. 
The beds incline at all angles from zero to thirty degrees, and 
even within short distances they may be found dipping in every 
possible direction. Twenty miles southwest of the line sup- 
posed to be traversed by the synclinal fold, for example at the 
lime kiln on Sugar creek, along the Cedar river above Roches- 
ter, at Cedar Valley, as well as at many intermediate points 
distributed promiscuously throughout the area of the Le Claire 
limestone, the beds stand at a high angle, and the multiplicity 
of directions in which they are inclined, even in exposures that 
are relatively near together, is wholly inconsistent with the 
idea of orogenic deformation. The beds are now praciically in 
the position in which they were laid down in the tumultuous 
Niagara sea. The principal disturbances they have suffered 
have been the results of epeirogenic movements which affected 
equally the whole region over v/hich these limestones are dis- 
tributed, as well as all the adjacent regions of the Mississippi 
valley. 
The exposures at Port Byron and Le Claire present some 
interesting features that are not seen so well at any of the 
exposures farther west. In the first place, the lime quarries at 
Port Byron show the characteristic oblique position of the 
strata, and at the same time they demonstrate that the oblique 
bedding is real and not a mere deceptive appearance due to 
cleavage of a mass of sediment that was originally built up 
regularly and evenly on a horizontal base. As in other groups 
of strata, there are faunal and lithological variations when the 
beds are compared one with another. These varjriug charac- 
teristics do not intersect the beds in horizontal planes as they 
would if the present bedding were due to cleavage of a mass 
that had risen vertically at a uniform rate, but they follow the 
