ANNIVERSARY ADDRESS OF THE PRESIDENT. lix 



1854. It is entitled *'An attempt at an historical account of the 

 geognostic conditions of the Thuringer Wald." It describes in a 

 clear and easy manner the different formations which occur in that 

 district, and the many disturbances which hare been effected in the 

 stratified beds by the protrusion of igneous rocks. The author 

 divides this history into three periods, the first two of which are the 

 most important. The first period commences with the oldest de- 

 posits, extending to the commencement of the deposition of the 

 Carboniferous rocks ; the second extends from the commencement 

 of the Carboniferous period to the commencement of the Trias 

 formation ; the third period embraces all the changes which the 

 Thiiringer Wald has undergone since the commencement of the 

 Trias formation. 



With regard to this latter period, however, the author observes, 

 that the great catastrophes on which depended the chief outline 

 and extent of the Thuringer Wald ceased at the close of the Zech- 

 stein formation. At this time the Thuringer Wald stood as an 

 island in the midst of the Secondary Ocean, round the shores of 

 which were gradually deposited the various Triassic beds, and from 

 which the ancient sea was gradually retreating. Other minor changes 

 subsequently took place, which influenced the form of the surrounding 

 hills and the formation of its valleys. I may here also mention, that 

 in the forthcoming geological map of Germany, one of the chief ob- 

 jects to which the attention of the German Geological Society is now 

 directed, and the preparation of particular districts of which has been 

 allotted to those members best acquainted with the respective locali- 

 ties, and who are all working on a given scale and with a fixed system 

 of colouring, M. Credner has undertaken the difficult task of pre- 

 paring the Geological Map of the Thiiringer Wald. 



I am happy to state that the valuable work of Drs. Guido and Fri- 

 dolin Sandberger, to whom, as you have already heard, the Council have 

 this year awarded the balance of the proceeds of the Woilaston Fund, 

 has made considerable progress during the past year. Two additional 

 fasciculi (Nos. 6 & 7) of this work, entitled *' Systematic Description 

 and Illustration of the Fossils of the Rhenish (Palaeozoic) Formation 

 in Nassau," have appeared since our last meeting, and I understand 

 that one more will complete it. To all students of the Devonian 

 formation on the Continent this publication will be invaluable. No- 

 thing can exceed the beauty and correctness of the illustrations, or 

 the judgment and talent shown by the authors in identifying the 

 several strata by their respective fossils. The literature of the dif- 

 ferent genera and species is carefully worked out, and great care and 

 acumen have been shown in comparing fossil families with their 

 living analogues. I might particularly instance the remarks on the 

 genus SchoUostoma, several species of which show in their last whorl 

 the peculiar turned-up character of Strophostotna amongst the ter- 

 tiary Cyclostom.acea and of Anostoma amongst living Helices. In 

 the form of the mouth, too, some of these species have a remarkable 

 resemblance with several species of Cyclostoma from the West Indies, 



