D4 ON THE GEOLOGY AND NATURAL HISTORY 
base of this section, between Manhattan and the Missouri. We even found a single 
specimen of this M/onotis as low down as bed No. 9 of the section taken near the landing 
at Leavenworth city, which must occupy a position several hundred feet below the lowest 
beds of the above section. Still as this shell is very rare in these lower rocks, and the 
Synocladia is a distinct species from the well-known Permian form of the Old World, 
while they are both, at these horizons, associated with great numbers of the common well- 
known Coal measure species, we can only regard their presence in these beds as establishing 
the existence of these genera at an earlier period in this country than in the Old World. 
This, it seems to us, is more philosophical than it would be to place all this great thickness 
of strata, with their vast numbers of well-known Coal measure species, in the Permian, 
merely because we also find with these occasionally a few forms which would in the Old 
World be regarded as characteristic of the Permian epoch. 
Taking it for granted, then, that we have carried this section down far enough to include, 
not only all the beds containing almost exclusively Permian forms, but a considerable 
portion of the upper Coal measures, it will be interesting to notice, as we ascend in the 
series, how far each of the Coal measure species mentioned in the lower part of the section, 
as well as of a few others that occur above and below, range upwards. ‘Thus we see that 
Fusulina cylindrica var. ventricosa, Chonetes Verneuiliana, and Retzia Mormonii, were not 
met with above division No. 37; while Spirifer planoconvexa, Productus splendens ?, and 
Rhynchonella Uta, were not observed above 34, nor Spirifer cameratus above 82. Fusulina 
cylindrica, of the slender variety so common in the Coal measures of Kansas and Missouri, 
was not seen above 22; nor was any species or variety of that genus observed above this 
horizon. 
Apparently the same species of Monotis, mentioned at various horizons far beneath, were 
occasionally met with in 30, 25, 23, and 20, generally associated with the same species of 
Synocladia, ranging far down into the upper Coal measures. In division No. 19, we again 
met with the Synocladia biserialis, and a Spirigera allied to S. subtilita, if not identical, 
along with a new species of Chonetes we have called C. mucronata, which ranges down 
into the beds near the base of the section. Along with these were also Productus Nor- 
woodii and Orthisina Shumardiana, both of which are common in the Coal measures far 
below, and a large Orthisina similar to O. wmbraculum, but apparently more finely striate. 
Ascending through the intermediate beds to No. 12, we continue to meet with nearly 
all the species mentioned in 19, with the exception of Chonetes mucronatu. We also have, 
first in 18, a large species of Productus, called P. Calhounianus by Professor Swallow ; 
very similar to some varieties of P. semireticulatus, but thought by Prof. 8. to present well- 
~marked internal differences. There is likewise added in 16 a large Allorisma, and a 
Spiriger similar to S. subtilita, but much more gibbous; and in 14, Discina tenwilineatus, 
