46 Correspondence — Mr. T. Davidson, 



It is imperfect knowledge on one subject, or on both, wbicli leads to 

 antagonism, and to all those unhappy bickerings which are so much 

 to be deplored. As Helmholz well said at the late scientific meeting 

 in Innspruck : — " Full knowledge of the truth always brings with it 

 the cure for the damage which imperfect knowledge may occasion." 

 Firmly convinced of this truth, let us continue our work with the 

 most perfect freedom and fearlessness, yet with modesty and in the 

 spirit of love, guided by a clear-sighted faith in 



" One God, one law, one element, 

 And one far-off divine event 



To which the whole creation moves." 



coias,E!Si=oi5riD:BnisrcE. 



NOTES ON CONTINENTAL GEOLOGY. 



Sir, — ^I am requested by M. Hebert to inform your readers that 

 he has just returned from a long journey, which he had undertaken 

 to study again the Upper Chalk in the North and the Titoniqiie in 

 the Alps. At Innspruck he met Prof. Zittel, a gentleman advanta- 

 geously known on account of his excellent worlc on the Cephalopoda 

 of Stramberg, and who now declares himself inclined to locate the 

 Limestone of Stramherg in the Neocomien, so that his own views 

 were apparently gaining fresh ground. 



M. Hebert desires likewise to make two rectifications of his 

 tables of classification of the Cretaceous system inserted at p. 20O 

 of last year's volume of the Geologicaij Magazine ; namely, that, 

 on account of the recent studies he has made in Sweden and Den- 

 mark, it would appear that he has placed the Limestone of SaWiolm 

 a little too low down in the series. Formerly it had been con- 

 sidered more ancient than the Chalk of Meudon and Norwich, and 

 in Angelin's Geological Map of Scania it is placed under the Chalk of 

 Tullstrop, which last is equivalent to the Chalk of Meudon and 

 Norwich with Belemnitella mucronata. 



In M. Hebert's table above quoted, and from observations made 

 by him in 1865, the limestone of Saltholm is placed above the Chalk 

 of Meudon, and he had assimilated it as to age with the Chalk of 

 Ignaberga, at well as to the gray beds of Ciply. Prof. Johnstrup,^ 

 of Copenhagen, and Dr. Lundgren, of Lund, have ascertained that at 

 Limhamn in Scania some beds of this limestone of Saltholm repose 

 on the Chalk of Taxo (Faxoe), that he has verified this fact during 

 his recent journey, but that at the same time, as will be hereafter 

 explained in greater detail, he believes he has made out that in 

 other localities some layers of this same limestone occur under the 

 Chalk of Faxoe. He has therefore been led to consider the lime- 

 stone of Saltholm as a simple fades of the Chalk of Faxoe as well 

 as the Limsteen, and that the three deposits will require to be 

 placed together in the same series with the Chalk of Maestrlcht. 



M. Hebert desires it also to be understood that the words 

 "wanting," "wanting," in his division of the Gault refer solely to 

 the columns in his table wliich are devoted to Touraino and Maine ■ 



* ? Steenstrup. 



