GEOLOGY. 
rocks, which are therefore termed primi- 
tive rocks, being chiefly composed of silex, 
alumina, and magnesia, constituting by their 
various intermixtures, 1, granite ; 2, gneiss; 
3, mica-slate ; 4, clay-slate ; 3, primitive 
lime-stone ; 6, primitive- trap ; 7, serpentine ; 
8, porphyry ; 9, sienite ; 10, topaz rock ; 
11, quartz rock; 12, primitive flinty slate; 
13, primitive gypsum ; 14, white stone. 
The circumstances which chiefly mark the 
high antiquity of these rocks are, that 
they form the fundamental rock of the 
other classes ; and that the outgoings of 
their strata are generally higher than those 
of the other classes. Having been formed 
in the uninhabitable state of the globe, they 
contain no petrifactions ; and, excepting 
the small portion which sometimes accom- 
pany those which will be next mentioned, 
they contain no mechanical deposits, but 
are throughout pure chemical productions. 
Small portions of carbonaceous matter oc- 
cur only in the newer members of the 
class. 
Before the summits of the mountains ap- 
peared above the level of the ocean, and 
before the creation of vegetables and ani- 
mals, a rising of the waters is supposed to 
have taken place, during which that class 
of rocks which are said to be of the second 
porphyry and sienite formation was de- 
posited. The rocks of this formation are 
of clay-porphyry, pearl-stone porphyry, ob- 
sidian porphyry, sienite, and pitch stone. 
They contain very little mechanical deposi- 
tions, are of complete chemical formation, 
and contain little or no carbonaceous mat- 
ter, and never any petrifactions. 
On the appearance of land, or during the 
transition of the earth from its chaotic to 
its habitable state, rocks which, from this 
circumstance, are denominated transition 
rocks, were formed. In these rocks the 
first slight traces of petrifactions, and of 
mechanical depositions, are to be found. 
The species of rocks which come under 
this class are the transition lime-stone, 
transition-trap, grey-wacke, and flinty slate. 
The petrifications are corallites, encrinites, 
pentacrinites, entrochites, and trochites. The 
lime-stone of Derbyshire is said to be of 
this kind. As the former class of rocks 
were purely of chemical formation, so the 
contents of these are chiefly chemical pro- 
ductions, mingled with a small proportion 
of mechanical depositions. To explain 
the cause of this mixture, we are referred 
to the period of their formation, that at 
which the summits of the primitive moun- 
tains just appeared above the waters, when, 
by the attrition excited by the motion of 
the waves, and which we are reminded ex- 
tends to np great depth, particles of the 
original mountains were worn off and 
deposited. 
As the height of the level of the ocean 
diminished, so would the surface on which 
its waves acted increase, and of course the 
quantity of the mechanical depositions. 
Hence these are much more abundant in 
the rocks of the next formation, which are 
denominated floetz rocks, on account of 
their being generally disposed in horizontal 
or flat strata. In these, petrifactions are 
very abundantly found, having been formed 
whilst vegetables and animals existed in 
great numbers. These rocks are generally 
of very wide extent, and commonly placed 
at the feet of primitive mountains. They 
are seldom of very great height, from 
whence it may be inferred, that the water 
had considerably subsided at the time of 
their formation, and did not then cover 
the whole face of the earth. Countries 
composed of these rocks are not so rugged 
in. their appearance, nor so marked by- 
rapid inequalities, as those in which the 
primitive and transition rocks prevail. The 
formations of this class are supposed to be, 
1, first or old red sand stone ; 2, first or 
oldest floetz lime-stone ; 3, first or oldest 
floetz gypsum ; 4, second or variegated 
sand-stone; 5, second floetz gypsum; 6, 
second floetz or shell lime-stone; 7, third 
floetz sand-stone; 8, Rock-salt formation; 
9, chalk formation; 10, fleetz-trap forma- 
tion; 11, independent coal formation; 12 , 
newest floetz-trap formation. 
Most of the rocks which have been just 
enumerated are covered by a great forma- 
tion, which is named the newest floetz trap. 
This formation also covers many of the 
high primitive mountains : it has but little 
continuity, but is very widely distributed. 
It contains considerable quantities of mecha- 
nical deposits, such as clay, sand, and gravel. 
The remains both of vegetables and ani- 
mals also occur very abundantly in these 
deposits. Heaps of trees and of parts of 
plants, and an abundance of shells and 
other marine productions, with the horns of 
stags, and great beds of bituminous fossils, 
point out the lateness of the period when 
this formation was deposited. In this for- 
mation several rocks occur which are also 
met with in other fleetz formations; but 
the following arc supposed to be peculiar 
to this class, basalt, wacke, grey-stone, por- 
