( 520 ) 



Scan{lina\'ia, from Hano\or, from the luoiintaiiis aloiiü' tlie hanks of' 

 the Rhine and from tlie Ardennes; I mt Sta itiNG was unable accurately 

 to define which erratics had been trans|)ortéd by the Rhine and 

 which by the Mense. 



"Ky far tlie largest portion of the (|iiartzites, sandstones. j)U(ldin<;- 

 "stones and slates, found in those |>arls of the dilnviiini, which arc 

 "situated to the South of the Scandinavian drift, are derived from the 

 "Devonian strata of the Rhine and the Ardennes." ') Neither did 

 Staring succeed in proving that the erratics in the diluvium of the 

 Meuse had originally come from the Ardennes. "The gravel and the 

 "flints of the Mense are similar to those of the Yehnve, with the 

 "important difference, howevei-, that no fragments of plutonic rocks 

 "are found among them."') 



Although for the last ten years the erratics transported from tlie 

 North of Europe have been tlie suliject of much careful investigation, 

 little interest has been bestowed on those derived from Southern parts. 

 This neglect is due in a great measure to the very nature of those 

 rocks. The first actual proof that detritus from the Ardennes has 

 been carried North of the Rhine, was supplied by J. Lori>1 when 

 he discovered a Rhynchonella Thiirmanni near Wageningen '); but 

 until now scarcely any further progress has been made, in the study 

 of this question. 



The diffienlty of tracing to their original home the boulders trans- 

 ported from the Ardennes, lies in the first place in the necessity of 

 leaving out of consideration, fragments of those rocks which are 

 represented both in the diluvium of the Rhine and in that of the 

 Meuse, for it is impossible to determine the exact districts to which 

 thev originally belonged. In the second ]ilace, it is a well known 

 fact that the greater part of the Ardennes is \ery poor in fossils, 

 so that the chance of finding fossiliferous specimens among the diluvial 

 erratics is almost nil; — and thirdly, some of the very characteristic 

 rocks, e. g. the phyllites, are much too soft to offer adequate resis- 

 tance to the accidents of transportation. However, as I hope to show 

 in the following pages sufticient material iVoni various formations 



^) 1. c. p. 97. 



2) I. c. p. 96. 



^) Contributions a la geologie des Pays-Ba.';. Arctiives Teyler (2) III. Haarlem 

 1887, p. 80. 



Postscript: Ferd. Roemeu has already mentioned silicified specimens of Stcpha- 

 noceras coronatum, found in the boulders near Winterswijk, Guelders. (N. Jalirl). 

 f. Min. 1854, p. 322, 323). These looked exactly like those occurring in the Jurassic 

 layers of Northern France. See also Gl. Schl titer in Zeitschr. d. D. geolog. Ges. 

 XLIX. 1897, f. 486. 



