498 JSenry Woodward — Old Land-surfaces. 



through our atmosphere, but would prevent its escape by radiation 

 after it had once heated the surface of the earth, and would thus 

 immensely augment the temperature of the lower strata of the 

 atmosphere, producing an effect precisely as if we had covered the 

 whole earth with an immense dome of glass — had transformed it 

 into a great orchard-house — and had thus established from the equator 

 to the poles, a moist, warm, equable climate, which would permit 

 even within the limits of the polar circle a luxuriant vegetation." ^ 



However ready we might be to accept Prof. Sterry Hunt's dictum 

 — if applied to pre- Carhoniferous vegetation, about which we know so 

 little — we cannot, with our present knowledge of the Coal-period, 

 and the requirements both of its animal and vegetable life, accept 

 his views, or admit them to be tenable, having regard to the known 

 fauna and flora of that epoch. 



Furthermore, the fact that precisely similar deposits are found to 

 occur in arctic as well as temperate and subtropical regions, does not 

 seem to us to prove " a moist, warm, equable climate established 

 from the equator to the poles," but rather proves that at particular 

 periods parts of the earth were then, as now, favoured with special 

 advantages, as regards climate, over other parts in the same degree 

 of latitude ; because, tJien, as now, the isothermal lines were (owing 

 to local circumstances of coast-lines, winds, and currents) deflected 

 from a straight course. 



Thus, as I have elsewhere pointed out (see GtEol. Mag., 1868, 

 Vol. V. pp. 297-303), at the present day, in the month of July, huge 

 icebergs may be seen off the east coast of N. America, in the same 

 latitude as London, with an atmospheric temperature of only 48° ! 

 Whilst the harbour of St. John's, Newfoundland, 2° further south 

 than Liverpool, has been blocked up with ice as late as the month 

 of June ! 



Surely if the small portion of the Gulf-stream which we enjoy can 

 effect such a deflection in the isothermal line as these two facts in- 

 dicate, what might it not be able to achieve under a different arrange- 

 ment of land, by which its whole volume might be made to pass in 

 a northerly direction. For we know that Greenland bears testimony 

 to two fossil floras — one in the Tertiary and one in the Carbon- 

 iferous period — and it seems highly improbable that an " envelope of 

 carbonic acid gas" was — if it ever existed — present at so late a period 

 as the Miocene Tertiary. If, then, this later flora flourished in this 

 exceptionally high arctic latitude, favoured by the varying eccen- 

 tricity of the earth's orbit, aided by the warm currents from the 

 equator, why should not the recurrence of such conditions, at an 

 earlier period, have sufficed to favour the production of the older 

 coal-beds ? 



Not for a moment questioning the proposition that in the earlier 

 ages of oiu" globe, its condition was very different both terrestrially 

 and atmospherically too (if chemists please) than at the present 



^ Chemical investigation shows that at the present day there is probahly as much or 

 more carbonic acid in the atmosphere in a free state as is in the whole mass already fixed 

 as carbon by plants and animals on the surface, aud by all the coal-seams put together. 



