PART I. 



Introduction. 



The field work on which the present paper is based was done 

 during the summer of '97 under the diredlion of Prof. H. S. 

 Williams. A few of the secftions studied then have been revisited 

 during the last summer while colledting fossils for the United 

 States Geological Survey. 



The sedlions studied extend from the top of the "Knobstone" 

 to the base of the Devonian. The area covered in the field in- 

 cludes a strip of country embracing the outcrops of these forma- 

 tions, which extends from the southern part of Bartholomew 

 county, Indiana, southward to Lebanon Juncflion, Kentucky, 

 and thence east to Crab Orchard, Kentucky, a distance of about 

 175 miles. 



The fadls which have been sought for in making and studying 

 the colledlions may be referred to four classes of data: Those re- 

 lating (i) to the geographical variation of the several faunas, 

 (2) to the range and distribution of species, (3) to the relation of 

 the several faunas to each other, and (4) the correlation of the 

 faunas of this region with those of the type sedlions. 



Stratigraphy and Nomenclature. 



The formations containing the faunas under discussion in this 

 paper constitute six terranes whose limits are more or less sharply 

 defined lithologically. Two of these formations are absent over 

 most of the area studied in Kentucky, but all of these are pres- 

 ent in southern Indiana. 



