﻿Notice of Dr. MantelVs Medals of Creation. 117 



are intermediate stages of this process, in which the form and 

 structure of the plants are apparent, and a gradual transition may- 

 be traced from the peat-wood and submerged forests of modern 

 epochs, in which leaves, fruits, and trunks of indigenous species 

 are preserved, to those accumulations of the extinct species of 

 an ancient flora, whose vegetable origin the eye of science alone 

 can detect." 



The author points out the distinction between cellular and 

 vascular structure ; the most simple plants have a cellular tissue, 

 consisting of a series of cells of the same kind, having no visi- 

 ble fructification; such are sea- weeds, (Algae, Confervas, &c.) 

 mosses and lichens. In the more complex tribes, the cells are 

 elongated into tubes or vessels, (vascular tissue.) some of which 

 possess a spiral structure, and others have their sides studded 

 with little glands, &c. 



The microscope, when applied to thin slices of fossil wood, is 

 of great service in developing their structure, and thus revealing 

 their nature. In this manner it is ascertained whether the tree 

 were endogenous, (increasing by expansion from within, and 

 having seeds with a single lobe,) or exogenous, (increasing by 

 annual additions on the outside of the wood beneath the bark, 

 and having seeds with two lobes, &c.) We cannot, in a brief 

 notice, follow the lucid explanations of the author, illustrated by 

 his beautiful figures, nor can we quote his excellent directions 

 for the microscopical examination of fossil plants. 



In writing of submerged forests and their long endurance, he 

 informs us that u the oak timbers of the Royal George, lately rais- 

 ed from off Portsmouth, after being immersed in silt about sixty 

 years, closely resemble in color and texture the sound wood of 

 the submerged forests.' 7 



In the peat bogs of Ireland, large forest trees are often buried 

 with the skeletons of elk, deer, and other animals of the chase, 

 and the primitive hunters with them wrapped in skins. 



In the celebrated Bovey coal of England, the wood as far as 

 observed by Dr. Mantell is coniferous, and is easily split or chip- 

 ped ; the layers of coal are from one foot to three feet thick, and 

 eighteen or twenty beds occur in a depth of about one hundred 

 and twenty feet ; this field of lignite extends seven or eight miles. 



In Iceland, although living wood is rare, beds of lignite called 

 Surturbrand abound. Jet is a compact lignite. It is abundant 





