306 Geological Societjj. 



tions of the past year *. Professor Hoffmann's map is to us of pe- 

 culiar interest ; not merely from the extent and intricacy of the 

 country it delineates; but also from the number of secondary for- 

 mations which it represents, in perfect conformity with the subdi- 

 visions adopted in our own geological maps. Works of this kind 

 are of inestimable value: thej' are the embodied results of observa- 

 tions without number, directed to one object ; and, when well per- 

 formed, may be regarded as the last generalizations from facts ex- 

 hibited in their clearest and simplest form. But more than this, — 

 they guide us to the fountain-head of information, and lead us to 

 still more general conclusions, by giving us at every step of our 

 way the means ot" comparison with the structure of other regions -f". 



To some admirable works on natural history, now in progress, 

 which bear more or less directly on our subject, I have no time 

 to allude. But I may point, with peculiar satisfaction, to the ad- 

 vancement of the work of M. Adolphe Brongniart on fossil plants, 

 and to the appearance of a new number of the work of Goldfuss 

 on organic remains. By the continued labours of these excellent 

 naturalists, we are supplied with new terms of geological compari- 

 son, and new means of legitimate induction. I am happy also to 

 announce the approaching publication of a general index to the 

 volumes of Mr. Sowerby's " Mineral Conchology," in which the 

 errors incidental to such a work will be corrected, and all the fos- 

 sils arranged according to their position in the successive groups 

 of the British strata. Such an Index has long been wanted ; and 

 its execution will be an advantage above all price to the student of 

 secondary geology. 



Each succeeding year places in a stronger point of view the 

 importance of organic remains, when we attempt to trace the va- 

 rious periods and revolutions in the history of the globe. Crystal- 

 line rocks are found associated with the strata of almost every 

 age ; and the constant laws of combination which have produced 

 a certain mineral form in rocks of one era, may produce it again 

 in another. Nearly all the modifications of structure in rocks called 

 primary are also found in secondary formations: and among tertiary 

 deposits we sometimes find millstone-grit, red marl with fibrous 

 gypsum, red conglomerates, compact, subcrystalline, and oolitic 

 limestone; in short, all the distinguishing characters of secondary 

 formations. The great barriers, which the fancy or ingenuity of 



* Dr. Klipstein has also executed a geological map (not, I believe, yet 

 published) of the districts north of the Main ; on the same scale, and of 

 the same extent, with the Odenwald map. 



t The geological maps of Germany are sold by Simon Schropp and Co. 

 of Berlin. I take this opportunity of observing, that the difficulty of pro- 

 curing copies of works like these has long been a matter of complaint. 

 Of the excellent geological map,' by MM. Oeynhausen, von Dechen, and 

 De la Roche, though published in 1825, not a single copy has, I believe, 

 yet found its way into the shops of any of our geographers. I only pro- 

 fiiredit myself at Berlin. 



geologists 



