ANNIVERSARY ADDRESS OF THE PRESIDENT. CXXTll 



Graphite, or crystallized carbon occurs, as is well known, in gneiss, 

 mica-slate, and other metamorphic rocks. The occurrence of frag- 

 ments of wood or other coal in igneous rocks depends of course upon 

 other circumstances, and has no bearing upon the question of the 

 age of such fragments. 



This sketch of the history of fossil carbon is so interesting, that I 

 have dwelt upon it longer than I intended ; and I shall therefore 

 compress into a small space any further remarks upon this work. 

 The great divisions of the Saxon coal-field may now be stated as 

 follows : — 



1 . The coal-formation of Hainich-Ebersdorf, which is the earliest 

 band of vegetation in Saxony. 2. The Sigillaria-coal, in which the 

 remains of such plants greatly predominate over all others ; this coal 

 is the lowest bed of the Zwickau basin. 3. The Calamite-coal, in 

 which a forest of Calamites, including some of the largest known 

 species, appears to have been buried ; mixed, of course, with species of 

 other genera. 4. The next zone also is rich in Calamites, though not 

 in the same proportion as in the one below ; the Calamites approxi- 

 matus being, however, most abundant. The Annularia longifolia 

 finds its peculiar horizon here, in which it appears to have attained 

 its highest development, though found both in lower and higher beds. 

 5. The last girdle or zone of vegetation is characterized by an abun- 

 dance of Ferns, since of ninety-eight species of plants, fifty belong to 

 this family of plants. 



The 5th zone has eighteen species in common with the 4th, the 

 same number with the 3rd, and even somewhat more with the 2nd ; 

 but, as Geinitz observes, it is not so much the relative number of 

 species, here so striking, which gives a peculiar character to the 

 flora, as the number of individuals, which must also materially affect 

 the nature of the coal. 



The coal-formation of Zwickau rests on strata which are considered 

 Devonian, and under these occur strata which are supposed to belong 

 to the upper portion of the lower Silurian, being rich in Graptohtes. 

 The upper Silurian is, according to Geinitz, wanting in Saxony. 



The plants from which the coal was formed lived during a period 

 of rest ; but, when the igneous rocks began to uplift the crust, cracks 

 were formed, heated steam arose, and in its passage through the 

 carboniferous deposits reduced some of them to mud, and then, being 

 condensed, poured down in heavy rain, by which dislocated frag- 

 ments of plutonic and metamorphic rocks were, with the slime, formed 

 into the grey conglomerate which now overlies the coal-deposits 

 of Zwickau, and is placed by Geinitz in the Permian formation. This 

 is a curious view of the mode of formation, and is illustrated in the 

 sections of the coal-deposits of Zwickau by several flows, as it were, 

 of the pulverized muddy matter through the broken strata. I shall 

 not further extend my remarks on this most interesting work, which 

 leaves nothing unnoticed, describing each important locality and 

 every form of rock ; and I shall conclude with a brief summary of the 

 fossils as given in a tabular form. No figures of fossils accompany 

 this part of the work. Of fishes, Lamna carbonaria, Germar, and a 

 Fish-coproUte are the only remains ; of boring insects there are traces 



