Geology of the Harz Mountains. 261 



products of erosion were deposited in the adjacent sea, and 

 are found in the Coal-measure and Lower Permian con- 

 glomerates which overlap the borders of the range. Volcanic 

 action was rife, and basalts, porphyrites, and quartz-porphyries 

 were erupted along the southern flanks of the district, while 

 the old palaeozoic core was invaded by dykes emanating from 

 the volcanic centres. 



The volcanos became extinct, and submergence began at 

 the end of the Lower Permian period. The highest of the 

 shore conglomerates underlies the Kupferschiefer seam of 

 Mansfeld, which was deposited at the beginning of the 

 Zechstein period, in a great inland lake extending from the 

 Harz southwards to the base of the Thliringer Wald in 

 Saxony. The area remained submerged below the sea in 

 which the Triassic, Jurassic, and Cretaceous formations of 

 the surrounding plain were being laid down. 



Signs of earth movement began to appear during the 

 Cretaceous period. The sea-bed was thrown into u.ndulations 

 with an E.S.E. and W.N.W. trend, and the Mesozoic rocks 

 were rent along one of the waves by a great fault, on the 

 southern side of which the rock mass of the Harz was up- 

 heaved to its present altitude. A seam of brown coal crosses 

 the line of fault at one locality, proving the movement to 

 have ceased before the Oligocene period. 



The Harz has not again been submerged, but was probably 

 partially covered by a portion of the great European ice- 

 sheet during the period of maximum glaciation. The 

 Secondary formations, under which it was deeply buried 

 when the upheaval took place, have long ago been swept off 

 by the action of the subaerial denudation to which the Harz 

 has been unceasingly exposed since the end of the far-off 

 Cretaceous Age. 



V. APPENDIX. 



A. LiTERATUKE. 



The literature on the geology of the Harz is very extensive, 

 and it is impossible to do more than notice some of the more 

 important works and papers here. A tolerably complete list 



