VITALITY OF BURIED VEGETABLE GERMS. 253 



of a very sterile heath in Staffordshire, some hundreds of 

 acres were planted with Scotch fir, and, after twenty-five 

 years, not less than twelve species of plants (not counting 

 grasses and sedges) had made their appearance in the plan 

 tation of firs, &quot;which could not be found in the heath,&quot; and 

 this though the fir-forest seems to have been visited only 

 by insectivorous birds. 



The existence of a succession of forests of different pre 

 vailing species has been satisfactorily established in Den 

 mark by the researches of Steenstrup on the Skovmose, or 

 forest-bogs of that country. These bogs are from twenty 

 to thirty feet in depth, and the remains of forest trees in 

 successive layers prove that there have been three distinct 

 periods of arborescent vegetation in Denmark first, a pe 

 riod of the pine ; secondly, a period of the oak ; lastly, a 

 period of the beech, not yet arrived at its culmination. 

 The dominant species of each period flourished to the en 

 tire exclusion of the other two species. Caesar affirms that 

 the Fagus (beech) and Abies (fir) were, in his time, want 

 ing in England ; but the beech is now plentiful ; and Har 

 rison tells us, in his &quot; Historical! Description of the Hand 

 of Britaine&quot; that &quot; a great store of firre&quot; is found lying 

 &quot; at their whole lengths&quot; in the &quot; fens and marises&quot; of Lan 

 cashire and other counties, where not even bushes grew in 

 h^ time. No doubt such extinct forests have flourished 

 in America, even since the Glacial Epoch, and have stocked 

 the accumulating soils with their stores of vitalized fruit 

 age, awaiting some future resurrection ; and no doubt the 

 &quot; fens and marises&quot; of Lancashire, under suitable circum 

 stances, would reproduce from their granaries of forest 

 fruit the arboreal vegetation which had flourished and 

 disappeared before the Roman Conquest. 



Mr. Marsh, in the work already quoted, after expressing 

 his opinion that the vitality of seeds &quot; seems almost imper- 



