152 Association of American Geologists and Naturalists. 
field was exhibited, which displayed in a beautifully distinct manner the 
woody fibre. 
The absence of trap dykes and dislocations in the western coal meas- 
ures, was adverted to, as a remarkable contrast to the coal fields of 
England, which are wonderfully disturbed by volcanic action and in- 
trusive rocks. The position of the most productive salt springs was 
pointed out on the section near the base of the coal measures. 
Rising from beneath the great Illinois coal field, and circumscribing 
it nearly in its whole extent, was a limestone, considered the equiva- 
lent of the mountain limestone of Europe, every where characterized 
by two very remarkable fossils—the Pentremite and Archimedes, and 
very important in practical economical geology, since no workable seam 
of coal has ever been found beneath the rock containing these organic 
remains ; they are, therefore, trustworthy guides in determining the 
limits of the western coal measures. 
Next in the order of succession followed a fine-grained sandstone and 
chert, interesting as being the repository of colossal beds of iron ore, 
not only in Tennessee, but in Kentucky and Indiana. _ It prevails in the 
region of country in these states known by the name of the Knobs. 
This formation has yielded some weak brines, but they have not been 
able to compete with those procured in the coal formation. 
The lower part of this formation was supposed to be the representa- 
tive of the Devonian system of England, and the Chemung group of 
New York. 
The whole of the above described groups of rocks rested on a black 
bituminous shale, very like coal shale, but unaccompanied by any per- 
fect seams of coal, and considered equivalent to the Marcellus shale of 
the New York geologists. 
The above comprised one half of the paper; the reading of the re- 
mainder was postponed for a future day, and Dr. Owen concluded by 
drawing up a summary of the foregoing in the form of a series of que- 
ries calculated to draw forth the comparative observations of others in 
distant parts of the west. 
Mr. James Hail then presented to the Association, a section 
intended to show the western relations of the New York strata, 
as developed in Ohio and other western states. 
The Chair mentioned to the meeting, that G. B. Emerson, Esq. 
would favor the Association with a lecture on the importance 
of natural history as a branch of education, on Friday evening, 
at 74 o’clock. 
The Association then adjourned. 
