1885.] SAND-PLAINS OF BELGIUM. 437 



cut up that it is impossible to recognise the objects seen through 

 them. The saud particles which come down from the heights of 

 the dune are blown against them, and have with their sharp angles 

 made thousands upon thousands of minute scratches, by which the 

 transparency of the glass has ultimately beeu completely destroyed. 

 An illustration of similar effects was brought under my attention at 

 Burntisland, on the Firth of Forth, lying on the north shore over 

 against Edinburgh. I was examining some beautifully - polished 

 fossils in the possession of a friend now deceased. They stood out 

 in basso-relievo and in alto-relievo from the material in which they 

 were embedded, as if artificially mounted for examination, and with 

 every lineament distinctly defined. I asked how he had succeeded 

 in so preparing his specimens. He told me he allowed the wind and 

 the sand on the shore to do it for him. And he took me to the 

 beach to see other specimens in course of preparation. There, 

 throughout a great portion of the year, westerly and south-westerly 

 winds prevail ; and when the tide ebbs, the sand is in constant flux, 

 a continuous current blowing across rocky ridges, all of which were 

 polished smooth on the surface over which the sand passed, while 

 all beyond, even where the protecting projection was minute, was 

 rough and unpolished. And there were shown to me several 

 geological specimens fixed by him in crevices, where they were being 

 polished in the same way, being changed in position from time to 

 time as occasion required. The drifting sand planed away steadily 

 at the comparatively soft, imbedding material, exposing the fossil 

 to whatever extent might be desired, but scarcely affecting this 

 beyond giving it a polish which brought all, or at least many of its 

 characteristics into view. 



I subsecLuently learned that the principle of action was utilized 

 in the United States of America to obscure glass by directing upon 

 it currents of sand propelled with regulated force, and I have seen 

 some beautiful specimens of figures tlius produced on glass. Of the 

 other phenomena mentioned in connection with this by Herr Wessely, 

 I have also had experience and opportunities of observing. Herr 

 Wessely goes on to say : " If one stays for a moment on the summit 

 of the dune, standing still and listening with attention, he hears a 

 gentle crackling sound, and feels on his hands, face, and eyelids, a 

 peculiar tickling sensation of prickly burning. Both the gentle 

 crackling and the tickly burning sensation on the skin are occasioned 

 by the fine sand, which is in constant movement." Continuing his 

 narrative, he mentions that ■' on the red cliff is a steep abrupt 

 precipice rising from 30 to 70 feet abruptly above the sand- 

 covered strand. It may be supposed that in connection with 

 such a case there is nothing can be said of sand - drift : but 



