X LETTER OF TRANSMITTAL. 



this dictionary is prepared as one of the Reports of the Board 

 to the Legislature of Pennsylvania for the use of the people of 

 the State. If citizens of other states iind it useful, well and 

 good ; but its contents have been selected with a single eye to 

 the requirements of Pennsylvanians owning or consulting co- 

 pies of the Reports of the Geological Survey, in which they 

 find a multitude of fossil names which need explanation and 

 illustration. Hence the lists of catalogued specimens in the 

 State Collection which occur thoughout the book ; and various 

 corrections of unavoidable mistakes made in originally label- 

 ling many of the specimens; a kind of information of no use 

 to foreign readers, unless they be professional geologists ; but of 

 the greatest interest to Pennsylvanians for giving them an 

 idea of the abundance of fossil- collecting localities in the 

 State, and directing them where to find them. Those who ex- 

 amine the Reports of Progress critically will perceive that I 

 have been as economical as possible in reciting the details, 

 while doing more than enough towards stating the case. 



The reader will notice frequent references to an Appendix, 

 especially in the first volume. This needs to be explained. 

 My first copy was ready for the State printer nearly a year 

 ago. Printing in fact began in the autumn of 1888, but was 

 soon necessarily delayed by reports from other State officials. 

 I hoped to have the first volume published during the session 

 of the Legislature, but the printing of it was stopped entirely in 

 the winter and spring by a mass of legislative documents requir- 

 ing immediate attention. I employed the time in enlarging 

 the work and in correspondence with fossil authorities in the 

 United States and Canada, a list of whom will be found in 

 front of the long list of Errata at the end of the volume. Thirty 

 of my correspondents, to whom I sent duplicate proofs of each 

 signature of sixteen pages, showed the greatest interest in the 

 work, returning the duplicates with their corrections and addi- 

 tions, directing me to better figures, sending me fresher and 

 better figures of their own, and, in fact, playing the most 

 friendly and valuable i61e of critics, reviewers, and I might 

 well say coeditors, to the extent of their ability as hard- worked 

 and much-occupied men. I was continually finding gaps in 

 my list and figures which I had missed. 



But more than all this, I had made the mistake of believing 



