350 S. E. Howorth—The Loess. 



contrast with the beds of real huraus intercalated with the Loess 

 in certain places (see Aughey, op. cit. p. 176). 



No doubt in Mongolia we have a high plateau covered with thin 

 grasses, and no doubt thin grasses will arrest moving dust. This 

 is a mere parallel to the office performed by the various siliceous 

 grasses in forming the dunes and sand hills of Holland ; but the sand 

 itself in Holland comes ready made, and, as I understand Baron 

 Eichthofen, the surface of the Gobi is formed of Loess ready made, 

 the grass merely arrests it in certain places when it is moving, it 

 does not help to make it. What we want to know is, how and where 

 it was or is being made either formerly or now. Let us now turn to 

 the European deposits of Loess. Whence did the wind bring them ? 

 They were clearly not made in situ by the wind acting on the drift 

 deposits and gravels underlying the Loess. Whence then did they 

 come ? 



If we turn east, west, north, or south of the great area of Euro- 

 pean Loess, whence are we to derive the dust which formed its basis 

 according to Baron Eichthofen ? Wind blowing over grass pastures 

 takes no dust — it must be over bare ground ; but where are we to 

 find such anywhere ? Again, if all the grass of the Eussian or 

 French plains was taken off. Baron Eichthofen will not argue that 

 wind blowing over the ordinary loam known as diluvium or over 

 the chernozom would carry off dust which, when deposited, would 

 he Loess. All this surely demands some answer, as does the 

 cardinal problem, that the Loess is a limited deposit in Europe with 

 sharp boundaries, especially towards the north. I can nowhere find 

 an answer to this critical question in Baron Eichthofen's paper. 

 Suppose we could find such a source for the dust, still our difficulties 

 would not be ended ; for the problem, as solved by Baron Eich- 

 thofen, requires that we should have quite exceptional conditions 

 besides. Take, for example, the demands upon our credulity involved 

 in the following sentence in his own paper : " The Loess-covered 

 portions of Europe extend, as is well known, from the Pyrenees, the 

 Alps, and the Balkan in the south, to Belgium, the North German 

 plains and Poland in the north, and from southern France in the 

 west to beyond the limits of the continent in the east. Every por- 

 tion of this entire region must have had the character of a steppe 

 during a sufficient length of time to allow the deposit to be formed 

 in at least such thickness as we observe at present" (op. cit. 301). 

 Where have we any evidence to supjjort such an extraordinary pos- 

 tulate ? Where is the evidence that this large portion of Europe was 

 a dry grassy steppe when the Helices and other damp-loving molluscs 

 were living here ? These and the debris of plants in the tufas are 

 very much better tests of the climatic conditions than hypothetical 

 appeals to a continental climate induced by Europe being prolonged 

 as far as the hundred fathom line, as if the presence of sea shells 

 mingled with those of the land, and with Mammoth remains, at the 

 mouth of the Somme, and at several points on our own coasts, do not 

 prove such a postulate to be out of the question at this particular 

 epoch. In Europe, therefore, so far as we know, there is no area 



