roofing the new buildings. At the depth of from 5 to 10 feet the 

 Forest marble has usually a deep indigo tint, but nearer the surface 

 it becomes rust-coloured. In some of the thick beds, used for pitch- 

 ing the streets, every stone is blue in the centre and yellow on the 

 outside ; the change is sudden and well marked, and is evidently due 

 (as stated by Mr. Way) to the conversion of a silicate of, the prot-oxyde 

 of iron into per-oxyde, for all our stone contains a small quantity of 

 iron, which rusts on exposure to the air or rain-water. The circum- 

 stance is of some interest, as it indicates the depth to which rain- 

 water carries down oxygen into the subsoil ; in the large joints and 

 fissures of the rock the rust colour is strongest, aud extends to the 

 greatest depth. 



The clay of the Forest marble is so variable in position, thickness, 

 and composition, that persons accustomed only to other clay soils, 

 would not be justified in predicating a single fact respecting it from 

 a casual inspection of the surface. I shall therefore cite the 

 information of those who have had most experience in the matter. 

 The surface soil has a cold gray or chocolate hue, which distinguishes 

 it at once from the warmer complexion of the corn-brash, and the 

 lighter tint of the Bath freestone. The clay itself (or rather marl, for 

 it always contains lime, and sometimes in large proportion) is some- 

 times bluish gray, and elsewhere (especially the lowest beds or 

 Bradford clay) of a light olive tint ; as, for example, in the drains 

 which are now making near the entrance of the Park. 



Mr. T. C. Brown says this clay is much benefitted by subsoiling, 

 but not by deep ploughing — it should never be brought up to the 

 surface ; and Mr. Bravender, in his Essay on Breaking up Grass 

 Lands, observes, that soils resting on this clay should be deepened very 

 gradually ; it should be done before the winter, so that it may be 

 exposed to the full action of the frosts, and requires to be plentifully 

 manured. Otherwise, an attempt to deepen the soil, even to the extent 

 of two inches, will injure the succeeding crops for several years. 



Mr. Arkell, whose management of this clay it is unnecessary for 

 me to eulogise, has pointed out to me that it differs from the Oxford 

 and other clays of the district, in the readiness with which it falls 

 to pieces with frost and rain, becoming light and hollow, so as to 

 require rolling and pressing to prevent the wheat plants from being 

 " thrown out " by the repeated falling away of the soil. Like 

 other clay soils it is not so well adapted for turnips or barley as for 

 wheat and oats, vetches and broad clover. Various parts of the 

 farm on the mixed clay and brashy subsoil are cultivated on the 

 three-fields, and four or eight-field systems, whilst the fields with a 

 subsoil of dry stone are kept under the five-field, or " Cotteswolds 

 hill " system. Most of the Forest marble district requires draining, 

 because even when the beds of clay are thin and interstratified with 

 stone, they will arrest the percolation of the rain-water for a con- 

 siderable time. The drains which Mr. Arkell has put in are from 3 

 to 4J feet deep, and from 24 to 40 feet apart, according to the depth 

 of the clay, and the presence or absence of stone. When the stone 



