66 TRANSITION SERIES. 
this benefit is the direct result of physical 
changes which affected the earth at those re- 
mote periods of time, when the first forms of 
vegetable life appeared upon its surface. 
The important uses of coal and iron in admi- 
nistering to the supply of our daily wants, give 
to every individual amongst us, in almost every 
moment of our lives, a personal concern, of 
which but few are conscious, in the geological 
events of these very distant eras. We are all 
brought into immediate connection with the ve- 
getation that clothed the ancient earth, before 
one-half of its actual surface had yet been formed. 
The trees of the primeval forests have not, 
like modern trees, undergone decay, yielding 
back their elements to the soil and atmosphere 
by which they had been nourished ; but, trea- 
sured up in subterranean storehouses, have been 
transformed into enduring beds of coal, which in 
these later ages have become to man the sources 
of heat, and light, and wealth. My fire now 
burns with fuel, and my lamp is shining with the 
light of gas, derived from coal that has been 
buried for countless ages in the deep and dark 
recesses of the earth. We prepare our food, and 
maintain our forges and furnaces, and the power 
of our steam-engines, with the remains of plants 
of ancient forms and extinct species, which were 
swept from the earth ere the formation of the 
transition strata was completed. Our instru- 
