146 GEOLOGICAL SURVEY OF ALABAMA. 
been much less completely removed, but remain to form the 
great bulk of the soils of that section. 
Of these later movements, it is not our intention to speak 
except in so far as may be necessary to explain the presence 
of these overlying surface beds which in places hide the 
formations with which we are now more particularly 
concerned. 
Il CLASSIFICATION OF THESE ROCKS AND 
THEIR DISLINGUISHING CHARACTERS. 
With this sketch of the manner in which the sediments 
were accumulated and afterwards brought up above sea 
level and into the positions in which they are now found, 
we may go on to speak of the distinguishing characters of 
the rocks with their contained fossils, of each of the great 
groups or formations Cambrian, Silurian, Devonian, and Car- 
boniferous, and to note the minor subdivisions into which 
they may be conveniently arranged for purposes of study 
and description here in Alakama. 
It would lead us too far to undertake to speak of the 
characteristic fossils of each of these formations, except to 
say that they are more unlike the forms of the present day, 
the further we go back in the geological scale, and the re- 
semblance to living plants and animals becomes more and 
more pronounced as we approach the top of our geological 
column; but in all cases, in the formations with which we 
are concerned in the present report, the resemblance of the 
fossils to living forms is rather remote. This has led to the 
grouping of the four formations above named into one 
division which has been called Paleozoic (Ancient Life), in 
allusion to the want of resemblance to modern forms. 
Except at a very few horizons, fossils are not abundant in 
our Alabama Paleozoic rocks, and rarely come under the 
notice of the ordinary observer, yet to the student of geology 
they are of the very greatest value since by means of them 
it becomes comparatively easy to determine the relative 
ages of the different formations containing them, when the 
stratigraphical relations of these rocks are not readily made 
out, Asan illustration of this I might say that there are 
