LETTER OF TRANSMITTAL. vii 



of dollars, counting in the publication of the reports ; or, for 

 the work itself a half a million ; that is, a total cost of fifty 

 cents in fifteen years, or three cents per annum, for each voter. 

 The Legislature has apx^ropriated for the survey an average of 

 $35,000 per annum ; a small outlay for so large and wealthy a 

 State to obtain knowledge of so practical a kind, — knowledge 

 which must be got somehow, and rmist be paid for somehow ; 

 either economically, by a State survey; or extravagantly, by 

 unorganized, haphazard and wasteful methods. 



Three years ago, in view of the fact that all the counties of 

 the State, 67 in number, would soon be surveyed and reported 

 upon, I began to prepare my final report or summary of the 

 geology of Pennsylvania. In the course of this work I en- 

 countered a difficulty in the shape of the innumerable fossil 

 forms which characterize the formations, and are recited in due 

 order and place in the county reports. At first I supposed that 

 I could deal with them by inserting wood cuts in the text, as 

 has been done in so many other State final reports. But I 

 found that this would swell the volume beyond all bounds, and 

 make it useless for most citizens of the State. At the same 

 time I was in receipt of many letters from quarrymen and pros- 

 pectors in various counties asking for information respecting 

 the strange forms which they noticed in the rocks. I had 

 always realized that the survey would leave unperformed one 

 of its necessary tasks if it did not fully explain the fossil geol- 

 ogy of the State, as a supplement to its mineral geology ; but 

 the practical work of the survey was so heavy that any ade- 

 quate report of its fossils had to be left to the very last. Mr. 

 C. E. Hall, the curator of the museum, made indeed a special 

 cabinet of fossils, and a catalogue of the same. Subsequently 

 Prof. Stevenson, Prof. I. C. White and Prof. Olaypole reported 

 the fossils of their respective districts ; and Mr. Carll and Dr. 

 Randall made considerable collections of fossils as well as min- 

 erals in the Oil region. In this way a good foundation was laid. 

 I then went through the whole series of the Reports of Pro- 

 gress, and made alphabetical card-catalogues of all fossil names, 

 localities and formations, which had been reported. I then 

 made similar catalogues of all fossils described by the New 

 York geologists found in the same formations. Doing the same 

 with the State Reports of Ohio, Indiana and Kentucky, 1 was 



