This paper briefly discusses Silurian lithology in parts of west Tennessee and adjacent States. Distinctive Silurian rock units are readily recognized in west Tennessee where they have been assigned to several formations and members by other geologists. In southeast Missouri the Niagaran strata have been regarded, hitherto, as a homogeneous sequence.
Lithologie similarities are stressed rather than stratigraphy and correlations in the regions considered. Lithologie aspects, including color, texture, earthy admixtures, presence or absence of chert, glauconite, and öolite are discussed. Persistence of certain beds and of fossil horizons is noted; some attention is also given to marked facies changes. Detailed comparisons are made between west Tennessee, southwest Illinois, and southeast Missouri, and the description and extent of the above lithologie features in selected areas in these States are presented.