Integrative Levels Classification project ILC2 schedules developing schedules how it works people references
ILC class i1X

ILC developing version
Expanded class i1X

   ▲  broader class

▽ ⌕         i1X            geological eras
▽ ⌕         i1XX                 geological periods; stratigraphical systems
▽ ⌕         i1XXX                      geological epochs; stratigraphical series
▽ ⌕         i1XXXX                           geological ages; stratigraphical stages
 
Connected classes:
 

specificity 
current: 99 

   
Move to another main class:
a b c d e f g h i j k l m n o p q r s t u v w x y

or

or insert a term and do a new