288 Scientific Meeting in Germany. 



nules which have burst and lost their colouring matter, and of which 

 the amorphous silica had been changed into crystalline. The 

 speaker's collections, and especially his microscopic preparations 

 of the finest organisms, excited in the section the utmost admira- 

 tion. 



At the sitting of Wednesday (September 23) General von Pan- 

 huys explained a small geological map of the southern portion of 

 the Duchy of Limburg, which he had prepared in 1850, by in- 

 structions of the Dutch War Office. The object had been to as- 

 certain whether the coal measures extended to the Dutch territory. 

 The speaker endeavoured to show that the Bardenberg district, 

 north of Aix-la-Chapelle, is connected with the Liege coal trough, 

 and forms a portion of it. Were this the case — a fact that can be 

 perfectly ascertained only by borings — Limburg would be in pos- 

 session of two square miles of coal measures, of which one-half is 

 covered merely by green sand and the other half by green sand and 

 by chalk. 



Herr von der Marck spoke on the subject of some petrifactions 

 of the Westphalian chalk, and exhibited a number of well-preserv- 

 ed fossils — amongst others, the remains of huge Saurians from 

 the Schcppiuger Berg, near Minister. 



Herr Heymann spoke of the changes of certain constituents 

 that had occurred in trachytic and basaltic rocks in the Siebenge- 

 birge. He exhibited specimens of oligoklas transmuted into kao- 

 lin and red Ehrenbergit ; of hornblende transmuted into steatite ; 

 . of transmuted augite and olivine in the basalt of the Menzenberg, 

 near Honnef ; radiated mesotype from the basalt of the Minder- 

 berg was also partly changed into a steatitic mass. 



Professor Noeggerath denied that the black mica in the trachy- 

 tes was altered hornblende. 



Herr Max Braun observed that the occurrence of blende at the 

 Wetternsee in Sweden, was something very different from what 

 it is in our known veins and beds in the district of the Rhine. In 

 Sweden the blende formed beds which were imbedded in the gneiss, 

 following the gneiss strata, with similar strike and dip, for a con- 

 siderable extent, and with a thickness of 15 to 20 feet or more. 

 The blende is for most part finely granular, and always intimately 

 mixed with more or less feldspath. In these beds of blende are 

 found concretions of green feldspath and of quartz, including 

 crystalline particles of blend. The gneiss in immediate contact with 

 the blende contains a bed of granular lime, containing garnet and 



