OOLITIC SYSTEM OF SCOTLAND. 871 
diminutive or few. Groups of large corals are characteristic 
of the intertropical seas, or at least of seas of either hemisphere 
that border on the tropics. I have seen an Isastrea of Helms- 
dale that measured about two feet and a half in length by about 
eighteen inches in breadth, and which, as I have said, a strong 
man could scarce raise from the ground; and arborescent masses 
of Thecosmila annularis have been found in the Coral Rag of 
England, that measured from a foot and a-half to two feet in 
height. There occur no such corals now in seas which lie be- 
tween the fiftieth and sixtieth degrees of latitude, whether to 
the south or north of the equator. And though I would not 
found much on one or two exceptional species, I do think that, 
seeing we would at once pronounce a similar group of re- 
cent corals to be the product of seas greatly warmer than our 
own, we might, I think, be permitted to infer, — reasoning from 
what we know, —that the Oolitic seas of what is now Scotland 
were of a higher temperature than our Scottish seas of the 
present day; and that, in short, in the corals of the Scotch 
Oolite we have one of many evidences that in this early period 
these northern regions enjoyed a greatly more genial climate 
than they do now. I may add, however, that in the same beds, 
mingled with fronds of cycas and zamia, and the stems of 
gigantic horsetails,—all now the productions of a warm cli- 
mate, and that seem to give evidence to the same fact as the 
corals, — there occur numerous fragments, and occasionally 
whole trunks, of fossil pines, that apparently testify, by their 
annual rings of small size, indicative of slow growth, to a cli- 
mate as ungenial and severe as that of Sweden or Norway. 
The evidence which they yield can, however, be scarce said to 
be of a conflicting character with that of the corals and the 
cycadites. If the Oolitic land was a lofty one, a very few miles 
might have served to separate a genial from a severe climate ; 
and the pines might have been brought down by rivers from 
