HARDWICKE'S SC lEN CE- G O S S ] P. 



79 



that many of the iibovc-iuentioned plants were not 

 identical with those living at the present time, but 

 with these we step upon the landing which opens 

 up the Englisli landscape. I would further remark 

 that it is not till the period under review that true 

 dicotyledonous trees, exogenous in their mode of 

 increase, bearhig reticulated leaves, and otherwise 

 higlily differentiated, are introduced. Indeed, pre- 

 vious to this period several whole orders, which 

 now minister abundantly to the wants of man, were 

 entirely wanted. xVs an example, the order Rosacese, 

 which gives us our apples, pears, peaches, apricots^ 

 quinces, plums, strawberries, raspberries, black- 

 berries, &c., was unknown. A further remark, 

 perhaps, may not be out of place here. In order to 

 understand and duly appreciate the history of fossil 

 plant-life, wc should not forget that, during our 

 progress upwards we have passed tbrougli many 

 gradations of progressive development, beginning 

 in the lowest rocks, with a flora humble in structure 

 and scanty in species, and ending with what we may 

 call the present plant-forms, the iiighest, most 

 varied, and most specialized. A knowledge of this 

 fact is deemed a potent weapon in the hands of 

 those biological speculators who believe in the 

 evolution theory. 



Fig. 50. Microscopical section of Fossil Wood from concre- 

 tionary nodules. Lower Coal-measures, Oldham. 



The fossil remains of plants now exhibited have 

 been disinterred from beds of rock differing widely 

 among themselves in the nature of the material of 

 which they are composed, and have been deposited 

 under very dissimilar circumstances. They all, 

 however, agree in belonging to the Carboniferous 

 epoch. Those of sandstone are but casts of plants 

 from the common building-stone of the neighbour- 

 hood, a rock which is intercalated with the seams 

 of coal and shale. These, along with those of the 

 shale, give no assistance to the investigator except 

 such as can be gleaned from their external forms 

 and markings. A few have been met with in con- 

 cretionary ironstone nodules, locally known as 

 " bullions," which are found numerously imbedded 

 in the shale, and one or two have been derived 

 from the floor-clay beneath the coal scam. This 

 floor-clay is the invariable accompaniment of coal, 

 and is probably the remains of the original soil in 



which these ancient plants grew. These specimens , 

 and those from the nodules in the shale, are seldom 

 met with containing reliable internal structure 

 The best light by which coal-measure fossil plant- 

 life is now read, is given off by the coal itself. Coal 

 is now made to yield up its own secrets, after a 

 silence of untold ages. The specimens of fossil 

 wood, by which the life history of the coal period is 

 now deciphered, are, as far as my own experience 

 of this locality extends, found imbedded in the coal. 

 A small seam, varying from a foot to eighteen 

 inches in thickness, and cropping out on the hill- 

 sides about Crow Knoll, Besom Hill, &c., and 

 known as the " upper foot seam," supplying the 

 entire yield in this neighbourhood. This seam of 

 coal is one of the " gannister series," otherwise 

 called the lower coal-measures. The nodules con- 

 taining the calcified plant-remains are in shape more 

 or less spherical, or long flattened ovals. These 

 fossil-bearing nodules occur in such numbers in 

 some parts of the above-mentioned seam as to 

 seriously interfere with the work of coal-getting 

 often causing the whole working to be abandoned. 

 It may perhaps not be unworthy of note that these 

 calcareous masses, though seldom known to contain 

 fossil shells themselves, are invariably accompanied 

 with a great abundance of shells in the shale above 

 the coal. Can it be that the triturated matter o 

 these shells, mingled with the estuarine mud (now 

 shale), has [furnished in part the material of the 

 nodular matrix, of this fossil wood, the matter so 

 provided aggregating itself round some object as a 

 nucleus? This limy matter, by surrounding the wood 

 with an envelope, has protected it from the destroy- 

 ing action of bituminization which had seized the 

 surrounding vegetable matter . The modus operandi 

 by which plant-remains have been preserved in these 

 nodules is not yet well understood ; therefore I 

 shall notice it but briefly. It is within the bounds 

 of probability that mineral and earthy matters, 

 while in a state of solution, enter the pores of the 

 vegetable tissue, and replace it, particle by particle, 

 as the original organism passes away. All the in- 

 formation that we can gather on extinct plant-life 

 points to the fact that species in geologic ages were 

 less numerous than at the present time. Indivi- 

 duals were, doubtless, as numerous in many periods 

 as now, but generic and specific differences, there 

 is reason to believe, were not proportionably abun- 

 dant. This is explained by assuming that the time 

 that had elapsed since the first introduction of 

 vegetable organisms, say to the Carboniferous age, 

 though immeasurably great, was but the early dawn 

 of a long biogenical day, during which the laws of 

 variability and specialization had not had sufiicient 

 time to exert their full influence. There appear to 

 have been fewer botanic centres then than now. 

 Types were more cosmopolitan— more widely 

 diffused over the earth's surface. It must not be 



