120 Notice of Dr. ManteWs Medals of Creation. 



Palm trees are often found petrified — the date and cocoanut be- 

 long to this family. A forest of palms is described by Dr. Owen 

 as occurring in Indiana in a member of the Illinois coal-field ; 20 

 or 30 trees were fijund with their roots in the clay, and their 

 stems in the coal and sandstone above, apparently in the place 

 where they grew ;* the form of the seeds left by the petioles in 

 the now carbonized bark indicates at least three species of palms. 



Silicified stems, probably related to palms, are very widely 

 distributed, and have been collected among the mammalian re- 

 mains in Asia and in the Sub-Himalayan mountains. 



Lignite is composed almost entirely of dicotyledonous trees 

 belonging to genera, and in many instances to species, namely, 

 poplar, willow, elm, chestnut, walnut, sycamore, maple, linden, 

 beech, thorn, &c. which are still inhabitants of Europe. The 

 lignites of the Rhine are the carbonized remains of drifted for- 

 ests like the rafts of the Mississippi, which may hereafter, in 

 their turn, become lignite. 



Silicified dicotyledonous trees are numerous in the Egyptian 

 and Lybian desert. About seven miles east by south from Cairo 

 a petrified forest lies in ruins, like an overturned modern forest — 

 the trunks crossing each other in various directions. Two of 

 the largest measured 48 and 60 feet in length, and 2^ to 3 feet 

 in diameter at the base. This forest reposes on a platform of 

 marine limestone, once the bed of the ocean, but now higher 

 than the level of the Nile. Vegetable matter occurs in all the 

 eras of fossil deposits. It is probable that many families, from 

 their delicate structure and from other causes, have entirely per- 

 ished ; those that have been discovered are naturally distributed 

 under three groups. 



1. The earliest, including the carboniferous, consists chiefly 

 of fuci, ferns, Coniferae, Lycopodias, and other families, analogous 

 to the vegetation of the islands and archipelagos of tropical cli- 

 mates. 



2. The middle epoch — from the new red sandstone to the 

 chalk — contains, prevailingly, Cycadeas, Zamiae, and other Co- 

 nifercB ; ferns are rare, and Lycopodias and Calamites of the coal 

 period are wanting. The flora is analogous to that of the mari- 

 time districts of New Holland and Cape of Good Hope. 



* This Journal, Vol. XLV, p. 336. 



