GLACIAL GEOLOGY OF NORTH GERMANY. 369 



and especially from Estlionia. The material derived from geological forma- 

 tions more recent than the Silurian seems to have come almost entirely from 

 the mountains of Northwest Germany and from the Eifel. The most prob- 

 able mode of transportation, according to Professor Martin, was by icebergs ; 

 by this supposition, at least, some of the theoretical difficulties are removed 

 which apparently could not be under any other hypothesis. He closes, how- 

 ever, with the remark that '' it is evident that in reference to our drift there 

 is a sufficiency of unanswered questions [genug ungeloster Fragen]."* 



In view of the large body of facts collected by the German geologists, 

 it seems necessary to admit the actual presence of ice — over portions of the 

 region, at least. Professor Credner, Chief of the Geological Survey of Saxony, 

 considers the evidence as decisive in favor of the former extension of the 

 Scandinavian ice sheet as far south in Saxony as the vicinity of Chemnitz, 

 a little south of the parallel of 51°. This opinion is based on the occurrence 

 of striated rocks at several localities,! and also on the character of the detrital 

 material on the surface. J The writer has examined in the Museum at Leipsic 

 the specimens of striated rocks collected by the Saxony Survey, and while 

 admitting that they ai'e the work of ice, does not consider it as proved that 

 this ice was not in the form of floating bergs or fields detached from a dis- 

 tant fixed sheet. The difficulties in the way of the adoption of any theory 

 of the occurrence and distribution of the detrital materials in this region are 

 very considerable, as may be inferred from the fact that Credner has to 

 admit that the glacial sheet moved up hill and in a direction just the opposite 

 of that in which the streams of the region were flowing at the same time.§ 

 Nor is the winter able to reconcile the statements made by the different geolo- 

 gists who have published in regard to the surface geology of North Germany. 

 No one has had so much to do with the examination of the " diluvium " of 

 that region as Dr. A. Jentzsch. He expresses himself in regard to the striated 

 surface of the Muschelkalk at Riidersdoi'f, considered by some of the Swedish 



* Niederlcindiseho uiid Nordwestdeutsclie Sedimeutargesehiebe, ihie Ubereiustimmung, gcDioiuscbaftliche Her- 

 kuuft, imd Petrefaoten. Leiden, 1878, ji. 59. 



t At Klein Steinberg and Tauclia, neai- Leipsic; at Landsberg, near Halle " s: and Lommatzseh, near Meissen. 



X See Credner, Uber Glaeialerscheinuugcn in Sachsen, in Zeitscbrift der deutschen geologisclien Gesellscbaft, 

 ISSO, Band XXXIL pp. 572-595; also, tJber die Vergletschening Norddeutschlands wahrend der Eiszeit, Ver- 

 liandlungen der Gesellscbaft fiir Erdkunde zu Berlin, 188(1, No. 8. 



§ " Tbe surface of Nortliwestei'n Saxony rises gently towards the southeast ; the rivers therefore flow in general 



in a northwesterly and northerly direction, and this laas tlic case already during ilie Glacial epoch The 



transportation of the native as well as of the Scandinavian material of the Northern ground njoraiiie took place 

 therefore in a direction opposite to that of the general direction of the streams." 1. c, p. 577. The reader will 

 notice the portion of the aljove statement italicized by the present writer. 



