SI' msrcAY OF 



From all these instances we see in what abundance petrifac 

 tions are to be found ; and, indeed, Mr Buffon, to whose ac- 

 counts we have added some, has not been sparing in the variety 

 of his quotations, concerning the places where they are mostly 

 to be found. * However, I am siuprised that he should have 



* Mr Kirwan remarks, that petrifactions are most commonly found in 

 ftiata of marie, chalk, limestone, or day ; seldom in sand-stone, still mure 

 larely in gypsum, &c. Tliey sometimes occur among' ores, and almost always 

 consist of the species of earth, stone, or other mineral, which immediately 

 surrounds them. Those of shells are generally found nearest the surface o! 

 the earth, those of fish deeper, and those of wood deepest. A very remark- 

 able circumstunce is, that petrifactions are found in climates where their 

 originals could not liave existed. From the gradual and insensible concre- 

 tion of this kind of matter from dropping waters, are found the large pendu- 

 lous columns, hanging like icicles from the roofs and sides of caves. The 

 most remarkable are in the Peak of Derbyshire. Sometimes they are found 

 in the arches of old bridges, and arise from water oozing through, and carry, 

 ing particles of lime with it. Petrifactions occur in three states ; some- 

 times they are a little altered; sometimes they are converted into stone; 

 and sometimes only the impressions of them, or the moulds in which they 

 have been enclosed, remain. Wood occurs in great abundance in many 

 parts of England, buried at various depths under the surface, and very 

 little altered either in its texture or properties. Pit-coal is supposed to be 

 of vegetable origin. One circumstance confirms this opinion, namely, the 

 existence of vast depositions of matter, half-way, as it were, between perfect 

 wood and perfect pit-coal; betraying obviously its vegetable nature, and 

 yet so nearly approximating to pit-coal in several respects, that it lias been 

 generally distinguished by the name of coal. 



No complete treatise on geological botany has hitherto appeared in this 

 country. Mr Parkinson's first volume, it is true, is dedicated to the consi. 

 deration of the vegetable kingdom. It contains descriptions and beautiful 

 figures of many varieties of fossil wood, plants, flowers, seeds, and fruits, 

 from various parts of Europe, and treats of the mineral and petrifying pro. 

 cesses to which they have been subjected. But at the period this writer 

 commenced his labours, no systematic classification or nomenclature had been 

 formed, nor was it known that this class of fossils was so numerous. The 

 preat source whence our geologists have hitherto drawn their knowledge of 

 antediluvian plants, is the splendid work, the Flora der Vorwelt of Count 

 Sternberg. In England the coal formations are particularly rich in beaud- 

 fully preserved plants. So far as they admit of comparison, they approach 

 those tribes of plants which now exist in warm climates, and luxuriate in 

 moist situations. They consist chiefly of palms and arborescent ferns, fScv 

 Plate I, fig. 1,; succulent plants, cacti, euphorbiae, canes, reeds, and gramina 

 The trunks or stems thus discovered, belong principally to arundinaoeou* 

 plants, approximating to those now known, partly to the palmaceous order, 

 and partly to anomalous forms, constituting a transition between these and 

 the coniferous plants. From the few comparisons which have been hitherto 

 Instituted between the plants of various distant coal fields, there is reason to 

 conclude that they have a general resemblance in all parts of the world : and. 



