Dr Fleming's Remarks on the Modern Strata. 117 
nected with one series, differs from the organised species of every 
other series, and that the inorganic materials of the series have 
likewise a co-existihg peculiar character. 
If we contemplate for a moment the genera of organised be- 
ings, we shall find that some of the species belong to the older, 
others to the newer series of strata, while some, still living, be- 
long to the modern epoch of the Earth. It is of great import- 
ance to attend to this distinction. Many geologists of eminence 
reason respecting genera instead of species, and, consequently, 
fall short of that precision which seems so desirable in geolo- 
gical science. Some examples on this subject are given in the 
paper on the Testaceous Annelides 
In the paper ‘‘ On the Influence of Society on the Distribu- 
tion of British Animals,” which appeared in the last number of 
this Journal, I entered upon several zoological details, serving 
to illustrate the characters of the species belonging to the mo- 
dern series of strata, and to demonstrate the imperfection of 
that classification whereby these strata are divided into diluvian 
and postdiluvian groups. In the present paper, it is my inten- 
tion to offer another arrangement, founded, not on considera- 
tions connected with the relics imbedded in these strata, but on 
the materials of which they consist, and the circumstances which 
have operated in producing them. 
The surface of the Earth 'is, at present, in an unnatural con- 
dition. Mountains rise above the level of the sea, and hollows 
exist beneath its level. What those causes have been, so much 
in opposition to the known laws of gravitation, which have pro- 
duced this unnatural state, we stop not here to inquire. But 
we shall be compelled, in prosecuting the object at present in 
view, to contemplate those causes which are operating in bring- 
ing the Earth into a natural state, by wearing down the project- 
ing parts, filling up the hollows, placing the surface every where 
at right angles to the direction of gravity, and perfecting the 
form of the Earth as a spheroid of equilibrium. It is difficult to 
arrange the strata belonging to the modern epoch of the earth’s 
history, into subordinate groups, because the different causes 
* The publication of the paper here referred to, in the present number of the 
Journal, has been prevented by circumstances connected with the late destructive 
fire in the neighbourhood of Mr Neill’s printing-office.— Ed, 
