INTRODUCTORY LETTER. 



Dear Sir : I herewith submit my report on the identification of the 

 veins of the Southwestern Coal Measures of Kentucky. 



Permit me first to most gratefully acknowledge the liberal and en- 

 lighteded support that I received from you, to ensure the success of 

 my researches. It is by following exactly your directions, that with 

 the co-operation of Mr. E. T. Cox, your able assistant, we are able to point 

 out now, for the first time, some general and reliable characters, which 

 may prove of practical advantage for the identification of the richest 

 beds of coal of Kentucky, and of the whole coal-fields of the United 

 States. 



It was understood that I should only have to collect and examine 

 the fossil plants of the Western Coal Fields of Kentucky, with essen- 

 tial references to the peculiar species of each bed of coal. You wantr 

 ed thus to ascertain the practicability of establishing the order of su- 

 perposition, and by this means, the identification of the beds. I had 

 been engaged during two years, in following the same researches for the 

 state survey of Pennsylvania, in the anthracite coal-fields of that state, 

 and had obtained some interesting and practical results from the study 

 of the fossil plants found in connection with the shales of each bed of 

 coal. But as soon as we began our explorations, in the bituminous 

 coal-fields of Kentucky, it became evident that the marine element 

 was predominant in the shales of most of the beds, and that it would 

 be of little advantage to limit our researches to the fossil botany 

 only, since shells and remains of fishes were mostly found in the 

 shales, without any plants whatever. For that reason, and confident 

 that the general principles exposed hereafter, would prove reliable for 

 the distribution of the shells, as well as of plants, I determined to 

 carefully examine the marine remains of each bed, and to collect them 

 for comparison and study. 



Mr. E. T. Cox, who is entitled to his share of the practical results of 

 our explorations, being better acquainted with the shells than I am, 

 took especial care of this part of our work, and by his unremitting 

 researches, and arduous labor, we have been able to collect a large num- 



