CORRIGENDA. 



Page 6, line 24, for " decrease " read " increase." 

 " 55, line 16, for " form " read " fern." 



" 55, line 5 from bottom, for " surrounding " read " succeeding." 

 " 57, line 19, after the word " trilobites " insert " in the carboni- 

 ferous." 



" 74, line 19, for " masses " read " mines." 



