Hardcastle. — On the Timarii Loess. 409 



. a fiue mud settled from pools of storm-water. This low-lying, 

 exceedingly tough and impervious material has in some places 

 retained stain-impressions of roots. 



Worm-borings. — Very satisfactory proof that the loess is a 

 dry-land formation is afforded by the fact that worm-borings 

 are to be found in it plentifully, in the dai'k bands, from top 

 to bottom. Most of them have been filled up by the worms, 

 as are recent borings ; but some are partly open, aiid the upper 

 part of the filling consists of loose distinguishable " casts." 

 It cannot be asserted that the lower borings were made by 

 worms working down from the present surface. The borings 

 are unmistakably more numerous in and just beneath each 

 brown-stain band than in the spaces just above these bands, 

 and they are in some places to be found beneath, and ter- 

 minating abruptly at, the mud-beds just described, which have 

 not been bored through at all. There are also to be found in 

 the stratum beneath it worm-holes plugged with this mud, the 

 plugs preserving the charactei-istic UTegularity, the departures 

 from cylindrical form, in the shape of the borings. The 

 " capillary texture " of the loess, mentioned by Sir J. von 

 Haast, is evidently due more to the multitude of worm- 

 borings than to the decay of roots, though this, no doubt, had 

 some influence in producing it. 



Evaporatio7i-vei7is.— Another evidence of the dry-land 

 origin of the loess, and of long pauses in its growth, 

 is the existence, beneath some of the lower granule-bands, 

 of what, for want of a known name, I must call "evapora- 

 tion-veins." Most clay-formations contain what excavators 

 call "backs " — natural vertical cracks — and these are usually 

 lined with a film of greater or less thickness of finer, whiter, 

 and denser material than the clay between them. In many 

 roadside cuttings these vertical veins are seen to streak the 

 clay quite thickly. If the vegetable soil be cleared away 

 these veins are seen to divide the subsoil into irregular figures, 

 rude pentagons being the most common form. In size the 

 figures vary from a few inches up to 2ft. in longest diameter. 

 A small number may be larger. 



I have never met with an explanation of these veinings, 

 and must attempt one. Whenever a soil cracks through 

 drought the cracks extend into the subsoil. The cracks in the 

 subsoil must be fine, as one never finds on digging into it 

 streaks of dark vegetable soil fallen into them. As the drying 

 of the ground in a drought proceeds, the moisture at' the 

 surface of the fissures will evaporate ; and that remaining in 

 each prism of clay will constantly endeavour, so to speak, to 

 maintain its capillary level, and will keep up the supply for 

 evaporation at the fissures. In thus movmg towards the 

 fissures, I conceive that the water drags with it such fine 



