ON COAL. 125 



transport yon in imagination to the surface of Sirias ; if I could draw 

 a picture of its physical geography, climate, and, more than all, of its 

 inhabitants, who in this audience would remain unmoved? Shall 

 the interest be less because the separation from us is by time instead 

 of space ; because the place is our own earth, and the materials of the 

 picture beneath our very feet? 



The coal period is a world distinctly separated from those which 

 precede and those which follow it. As in the geographical distribu- 

 tion of fauna and flora upon the surface of the earth at the present 

 time, we find in some cases contiguous fauna and flora seem to inter- 

 penetrate or pass by insensible gradations into one another ; the 

 species on the confines of each dying out in number but not in specific 

 character, insensibly replaced but not ty-ansmuted. So also in the dis- 

 tribution of fauna and flora in time we find some (as, for instance, 

 those of the- tertiary) which pass by insensible gradations into one 

 another, or interlock with the preceding and succeeding, although 

 only by gradual replacement, not by transmutation. But as in 

 geographical distribution we also find many fauna and flora com- 

 pletely isolated by physical barriers, mountain chains, oceans, or 

 deserts, from contiguous fauna and flora, so also in geological dis- 

 tribution we find creations are often distinctly separated from other 

 creations contiguous in time, by physical barriers in the form of con- 

 vulsions of the earth, and marked by broken, dislocated, and upturned 

 strata. In the history of the earth there seems to have been many 

 such successive creations completely destroyed by convulsions ; in 

 other words, the time-worlds are apparently separated by blank 

 spaces, whose dimensions we have no means of estimating. Such a 

 distinct world is the coal period, with its fauna and flora distinctly 

 separated from the old red sandstone which precedes, and still more 

 so from the new red sandstone which succeeds. A distinct world — 

 completely circumscribed in time — having its own poles and equator. 



Now, in geology, history is recorded upon tablets of stone — stratified 

 rocks. Time is represented by their thickness; remarkable events by 

 their dislocation ; the fauna and flora by the contained fossils. Let 

 us, then, examine the strata which represent this period. 



They are called the "carboniferous strata," and the period the 

 " carboniferous period," from the remarkable fact that they contain 

 almost all the coal which is found in the world. The deposit of car- 

 bonaceous matter is not indeed confined to this period, for it has oc- 

 curred in every period of the earth's history, as evidenced by the fact 

 that thin seams of coal are found in all the strata. Similar deposits are 

 still going on in peat bogs and. deltas of the present day. But the accu- 

 mulations of carbon in the strata of which we are speaking are so enor- 

 mous, in comparison to those found elsewhere, that the name carbonife- 

 rous, as applied to these strata and this period, becomes entirely appro- 

 priate. With the single exception of the oolite strata, which belong to 

 the secondary period, and in which coal is profitably mined in Virginia 

 and in England, all known coal mines belong to the carboniferous 

 strata. The knowledge of this simple fact would have saved the 

 useless expenditure of millions of dollars, both in this country and 

 in England. It is worse than useless to expend money and labor in 



