the word " speries " on page [83] are corrected in the later edition. 



2. The words " Saurian family " are replaced by the compound 

 " Enalio-Sauri " on p. [91] ; and the word " shewn," p. [84] is 

 replaced by the more modern form " shown " on p. [92]. 



3. The arrangement of localities under " Medial Tertiary or 

 Older Pliocene," p. [92], follows no special geographical order, 

 but is the same as that under " Older Pliocene "and " Miocene," 

 p. [84], with the word " Miocene" stricken out. 



4. On page xv. of Conrad's "Medial Tertiary," published in 

 January, 1838, he remarks regarding the relative number of re- 

 cent and extinct species found in this division of the Tertiary : " I 

 was formerly led to believe that we had forty recent in about 

 two hundred species." This belief " formerly " held by Conrad 

 (i. e., prior to Jan., 1838), is clearly stated on page [92] of the 

 present work. 



Therefore, it is evident that pp. [85-92] were published sub- 

 sequent to Mar. 1, 1835, and somewhat prior to Jan., 1838. 



Plates 19 and 20. These plates were apparently never pub- 

 lished in the strict sense of the word. They occur bound up with 

 other matter forming a so-called " Appendix" to the copy of 

 "Fossil Shells, &c.," belonging to the Museum of Comparative 

 Zoulogy of Harvard University. The names of all the species 

 but one have been written in with a lead pencil on the plates 

 themselves. Plate 19, figure 1, is evidently a representation of 

 Cytherea nuttallii Con., and accordingly.it has been designated 

 so on p. 115. Plate 20 is so numbered very faintly on the original. 



It seems quite possible that these plates were struck off as 

 proofs for a contemplated Number that should embrace a revision 

 of the Claiborne bivalves similar to that of the univalves (Re- 

 publication of No. 3). Moreover the revised form of "Observa- 

 tions on the Eocene deposits of the United States," pp. [85-92], 

 may have been intended primarily to accompany this Number 

 which never appeared. .GILBERT D. HARRIS. 



Washington, April 6, 1893. 



[81 



