452 DISTRIBUTION OF 
that an analogous distribution of the fossil sub- 
merged Algse appears to have placed in the 
lowest and most ancient formations, genera allied 
to those which now grow in regions of the greatest 
heat, whilst the forms of marine vegetation that 
succeed each other in the Secondary and Ter- 
tiary periods, seem to approximate nearer to those 
of our present climate, as they are respectively 
enclosed in strata of more recent formation.* 
If we take a general review of the remains of 
terrestrial Vegetables, that are distributed through 
the three great periods of geological history, we 
find a similar division of them into groups, each 
respectively indicating the same successive dimi- 
* See Ad. Brongniart's Hist, de Veg. Foss. 1 Liv. p. 47. — 
Dr. Harlan in the Journal of the Academy of Nat. Sc. of Phila- 
delphia, 1831, and Mr. R. C. Taylor in Loudon's Mag. Nat. 
Hist. Jan. 1834, have published accounts of numerous deposits 
oifucoids, as occurring in repeated thin layers among the Transi- 
tion strata of N. America, and extending over a long tract on the 
E. flank of the Alleghany chain. The most abundant of these is 
the Fucoides Alleghaniensis of Dr. Harlan. Mr. R. C. Taylor has 
found extensive deposits of fossil Fuci in the Grauwacke of central 
Pennsylvania ; in one place seven courses of Plants are laid bare 
in the thickness of four feet, in another, one hundred courses 
within a thickness of twenty feet. {Jameson s Journal^ July, 
1835, p. 185.) I have also seen Fucoids in great abundance in 
the Grauwacke- slate of the Maritime Alps, in many parts of the 
new road between Nice and Genoa. I once found small Fucoids 
dispersed abundantly through shale of the Lias formation, from a 
well at Cheltenham. The Fucoides granulatus occurs in Lias at 
Lyme Regis, and at Boll in Wurtemberg ; and F. Targionii in the 
Upper Green-sand near Bignor in Sussex. 
