Correspondence — Dr. Anders Hennlg. 287 



the only course by which they can be properly tested ; that is 

 to say, by tracing for themselves the isobathic contours on the 

 Admiralty Charts by means of the soundings. 



Before concluding I wish to call attention to a remarkable 

 corroboration of these views which has recently appeared from 

 another quarter. In his elaborate work on the Ghacial Geology of 

 the Christiania Region of Norway, in which the variations of level 

 at successive epochs are elaborated, Professor Brogger ^ says : 

 " the occurrence at great depths of the Norwegian Sea of the high- 

 arctic fossil shallow-water Mollusca of the ' Yoldia fauna' is 

 explained by the hypothesis, that the sea-bottom during the time of 

 the greatest ice-sheet of Europe must have been uplifted at least 

 2,600 metres higher than it is at the present." It is remarkable 

 that this amount of uprise corresponds very closely with that 

 determined by myself; nanleh^ 1,200 fathoms (7,200 feet) as the 

 elevation of Western Europe during the intensest cold of the Glacial 

 period. The maximum elevation was coincident with the stage of 

 maximum cold of that long period ; they were, in fact, cause and 

 effect. We require no other explanation for the cause of the intense 

 cold, and the subsequent changes of climate, than the oscillations of 

 level of land. Edward Hull, 



THE UPPERMOST CHALK OF THE BALTIC. 



Sir, — In his valuable communication " On some Crustacea . . . 

 from the Upper Cretaceous of Faxe" (Geol. Mag., Nov. 1901, 

 p. 487) Dr. Henry Woodward has copied from Dr. K. 0. Segerberg's 

 paper "De Anomura och Brachyura Dekapoderna inom Skandinaviens 

 Yngre Krita " (Geol. Foren. Stockholm Forhandl., xxii) certain 

 statements concerning the geology of the Baltic Uppermost Chalk 

 (Yngre Kritan). Since these might mislead English readers, I ask 

 leave to correct them. 



Since ' Faxekalk ' is identical with ' Corallkalk,' it is incorrect 

 to say that '• The lower layer of the Faxe Chalk is ... . largely 

 composed of corals, hence called coral-chalk." Even if the term 

 ' Faxekalk ' be applied to the whole of the Uppermost Chalk, the 

 expression is misleading, since the bottom bed of the Uppermost 

 Chalk does not consist of the Corallian Limestone (Faxekalk sens, 

 str.), but this latter itself rests on a bed of coccolith-limestone 

 (Saltholmskalk). 



The hardness of the coccolith-limestone depends on a secondary 

 cementing through calcite-crystals or flinty matter, a process in no 

 way restricted to any definite horizon ; looser varieties of this 

 limestone are found just as much in its lower levels as " in the 

 upper layer." 



The coccolith-limestone forms the main facies ; here and there 

 on the coccolith-ooze there sprang up coral banks or groves of 

 bryozoa ; but the shower of coccoliths proceeded unchecked, so that 



1 " Om de Senglaciale og Postglaciale Nivaforandringer i Kristianiafeltet," 

 pp. 682-3. 



