2l)S The A'lierii-iiK Geologist. Novcniinr, 1896 
In seeking for a criterion tluit is fundanicntal in strati- 
graphy it is p;>rtinent, at the outset, to in((uire into tlie real 
nature ol" s^ilini citation, into the causes producing it, modi- 
fying it, and limiting it, into the forces called into action in 
subsequently obliterating their results, in fact into all of the 
primary processes involved and into the secondary processes 
which tend to obscure tlie acM-ual workings of the real and 
fundamental laws. Only in this way can the main object in 
the establishment of an adequate and elastic system of geo- 
logical correlation hi attained and a ready interpretation of 
the history of terrestrial phenomena be made. Since from 
th3 strata of the globe must hi decipliered the records of its 
hist)ry, th3 leading facts to b3 ever borne in mind and to be 
recognized to their fullest possible extent are that the ele- 
ments of s?diui3ntation are in large part the products of land 
decay, which form seaward-creeping fringes around the con- 
tinental areas, and that the cessation of the action of the 
processes favorable is one of the prime factors in beginning 
each new cycle or great epoch in the physical history. 
Since sedimentation goes on most actively along the bor- 
ders of the great land masses of the globe, it is mainly a func- 
tion of continental growth and decline. Its most important 
relation is with the shore-line, for the latter marks the bound- 
ary along which two very ditt'erent processes are continual- 
ly in action. On the one side degradation of the land is 
constantly carried on ; on the other material is being con- 
tinually deposited. To the rising or sinking of the land 
with reference to the sea, or to the continual advance or re- 
treat of the shore-line are to be ascribed all the wide-spread 
changes in the character of the deposits thrown down in any 
particular place, and it is the variation in level chietij' 
that gives rise to the intricate and apparently lawless suc- 
cession of lithologically different layers. 
The immediate causes for the changes between the rela- 
tions of the land and sea areas are to be sought in orogenic 
and epeirogenic movements. As the two kinds of move- 
ments cannot be readily separated practically, and as it is 
of small advantage to separate them theoretically, the re- 
sults produced may be all regarded as arij^ing from the one 
cause, from mountain-making forces. The greatest and most 
