l^atural History in London. 26^ 



" The fossil stems, which are the immediate subject of Dr. Buckland*s 

 paper, like the recent Cycadeae, are not covered with true bark, but have a 

 thick case, made up of the basis of decayed leaves, which externally form 

 rhomboidal compartments, similar to those of the recent plants. The in- 

 ternal structure in the fossils, so far as hitherto examined, resembles that 

 of the Cycadeae, except in the more external position and greater breadth 

 of the circle or circles visible in the section of the stem, a character where- 

 by, Mr. Brown is of opinion, this fossil family approaches more nearly than 

 the Cycadeae, to the ordinary structure of dicotyledonous woods ; and con- 

 sequently may be considered as supplying, from the fossil world, a link 

 which helps, in some degree, to connect the still distant structure of the 

 cycadeae with that of the nearest existing family, the Coniferae.^ 



" M. Adolphe Brongniart's publications on the history of fossil vege- 

 tables, though produced in another country, are too important to our en- 

 quiries not to be mentioned here. Some fear, perhaps, may be entertained, 

 that his data are not yet sufficiently extensive to form an adequate base for 

 his deductions ; but there can be no question as to many of his inferences, 

 nor respecting the impulse which the subject will receive from such an 

 accumulation of facts as he has brought together. His views contrasting 

 the climate of the globe at former periods and at the present time, and 

 his division of the epochs of geological deposition, as deduced from the 

 study of fossil plants, in comparison with those which mere geological en- 

 quiry points out, are most ingenious. Even if regarded as no more than 

 the conjectures of so acute and indefatigable an enquirer, these speculations 

 would be well deserving of attention ; and, altogether, his works on fossil 

 plants must be considered as constituting one of the most valuable contri- 

 butions to this department of geology that has ever appeared." 



We are obliged to pass over various subjects of the greatest interest, in 

 order to find room for an extract from the President's very interesting con- 

 clusion : — 



" Such, Gentlemen, is a brief statement of the product of our labours 

 during the past year, and of some of the objects which you may perhaps 

 regard as still deserving your attention. If, on comparing our subject with 

 some other departments of physical research, we lament that we cannot 

 avail ourselves of such aid as mathematical science furnishes to the astro- 

 nomer; if the phenomena we are occupied in observing be inferior in sub- 

 limity to those presented by the heavenly bodies, and the laws we investi- 

 gate less striqt than those which govern their motions, — still do our 

 enquiries claim a very high place as an exercise of intellectual power. The 

 geologist, like the astronomer, is called upon to trace the effects of forces, 

 not only vast beyond conception in themselves, but acquiring almost infinite 

 augmentation of effect, from the numberless ages during which they have 

 been unremittingly exerted: and the problem, to explain the condition of 

 the earth's surface at any moment of this career, is complicated as much, 

 perhaps, as any other in physics, from the nature of the agents, of which 

 change and irregularity appear to be essential characteristics. The degrad- 

 ation of the surface by the atmosphere, the erosion of streams and torrents, 

 the encroachments of the sea, the growth and decay of the organised beings 

 that successively inhabit the globe, with all the chemical and mechanical 

 changes going on around us, though constantly in operation, are for ever 

 varying in their energies and effects. The great phenomena of volcanic 

 agency, which seems as it were to constitute one of the vital powers of the 

 earth, are from their very nature transitory and erratic. Viewed, never- 

 theless, in relation to the vast periods of time during which phenomena of 

 the same kind have been continually recurring, these very accidents and 

 apparent irregularities acquire a sort of uniformity. They intimate the re- 

 petition of results in future, resembling those which seem already to have 

 occurred repeatedly in the history of the globe ; and that part of the Hut- 



