PREFACE. V 



differing gender, and in such cases there is placed after the species 

 name the appropriate endings in the order mascuHne, feminine and 

 neuter ; so that the proper endings may in each case be noted. When 

 the endings in the species index disagree with the endings as given 

 in the body of the work, the latter is to be regarded as erroneous. 

 For the endings of specific names derived from proper nouns, a 

 rule usually observed, is that names ending in final mute e change 

 it to i and add a second i — as Lane, lanii ; Barrande, barrandii, but 

 names ending in consonants, or other vowels take only one i, e. g,, 

 Hall, halli ; Conrad, conradi ; Dewey, deweyi, etc. Another rule is 

 to drop the final a of a locality name when the ending is ensis; 

 thus — Iowa, iowensis, Canada, canadensis, though iowaensis and 

 canadaensis are often used. Final e is also dropped, as Delaware 

 — delawarensis ; Tennessee, tennesseensis. Other vowels are 

 however retained, as Colorado, coloradoensis, Mississippi, missis- 

 sippiensis ; final y after a consonant changes to i, as Kentucky, 

 kentuckiensis, but not after a vowel — e. g., Jersey — jerseyensis. 



To the acknowledgments made in Vol. I, should be added one to 

 Professor Charles Prosser, who revised some of the proof of the 

 Stratigraphic Summary. 

 New York and Boston, 

 May 15, 1910. 



