290 ON THE SOILS AND SUBSOILS 



standards and coppice show an excellent growth, and the timber 

 formed is of good average quatity. 



2. The sands of the Keupcr and Lias formations. — The Keiiper 

 sand (Triassic system), in which the grains of quartz are united 

 at one time by a siliceous, at another by a limy, and again by a 

 clayey cement, and throughout which numerous deposits of marl 

 and stiff potter's clay occur, necessarily forms on decomposition 

 soils of varying quality. The lower portion of the formation 

 yields a yellow, deep, loamy-marly soil of great fertility. This 

 is very suitable for tlie oak, which here forms excellent timber, 

 either mixed with beech, or as standards above an undergrowth 

 of beech or Norway spruce. But it does not thrive on the poor, 

 whitish, siliceous, coarse sand of the upper deposits, which are 

 Mf anting in earthy substance, and become easily heated ; such a 

 soil scarcely affords nourishment to the Scotch fir. The Lias 

 sand (Politic system) is, like the better varieties of the Keuper, 

 extremely well suited to the growth of oak. It in general 

 produces a more marly, yellowish, deep, fresh, sandy loam. 

 Grecnsand. (cretaceous growp, Ger. quadcrsandstein) is fine grained, 

 and contains a scanty clayey or siliceous cement. The more 

 quartzose varieties are not easy of decomposition, while the 

 clayey kinds are soft, and soon form a loose, poor, very sandy 

 soil, apt to become dry, and which is on the whole less fertile 

 than hunter sand of the dark red kind, being not well adapted 

 for the rearing of oak timber. It occurs extensively on the 

 Deister hills near Hanover, and beeches are chiefly cultivated 

 on it, with sprv^ce and Scotch fir on the worst spots. 



Among the more sandy soils of the Tertiary and post-Tertiary 

 periods are : — 



3. The Quartz-sand or Aretaccous Quartz of the North German 

 plain, containing frequently 90 per cent, and upwards of quartz, 

 and therefore not suitable for the oak, being loose, dry, and barren. 

 Over some parts of the plain, however, oaks are found in excellent 

 growth, as in the Mark Brandenburg, see page 288. This was 

 long held as anomalous, but in analysis by Prof. Seuft, of the 

 Forest School of Eisenach, such sand was found to contain 17 

 per cent, of grains of feldspath. 



4. The fertile, loamy sands, which produce oaks of immense 

 size. Here the tap-roots find an easy passage through the deep, 

 fresh soil, and the rootlets convey abundant supplies of moisture 

 through the ascending axis to the leaves. Here the oak has the 

 greatest annual increase of growth, and produces excellent 

 timber. Over such a soil are the largest oaks of north Germany. 

 They grow in Uilenriede, a pleasure wood adjoining the town of 

 Hanover. 



Limy Soils. — These we may subdivide into three heads : — 

 1. Clayey limes, produced by the more easily decomposible 



