122 Scientific Proceedings, Royal Dublin Society. 



The soils due to the "weathering of most of the highly meta- 

 morphosed rocks are in part allied to the granitic soils ; but as 

 such rocks are of different compositions and characters, the 

 resulting soils are variable ; strips of land over and adjoining- 

 calcareous and some argillaceous rocks being good, while the rest 

 may be bad and unprofitable. 



Rocks of Cambrian and Cambro-Silurian ages, which are not 

 very silicious or highly metamorphosed, weather to a considerable 

 depth, and in most cases their detritus is capable of being con- 

 verted into profitable land by subsoiling, drainage, and liming ; 

 lime being necessary to dissolve out the iron, so prevalent in such 

 soils ; in most cases, however, the iron cannot be got rid of unless 

 the land is drained as well as limed. Subsoiling is especially 

 necessary in those areas where, between the surface and the solid 

 rock, there is a " shingle " or " rubble," through which most of the 

 soluble parts of the manures applied to the surface will drain 

 away ; if, however, the shingle is ripped up and mixed with the 

 surface soil, these parts of the manure would remain in the 

 land. Here it may be pointed out that the natural value of land 

 depends not only on the soil, but also on the subsoil. A stiff 

 retentive soil with a clay subsoil would not be of the same value 

 as the same soil with a gravelly subsoil ; while a light, friable 

 soil with a gravelly or shingly subsoil would not be of the same 

 value as the same soil over a retentive subsoil. In the first case 

 the subsoil would retain moisture to the injury of the surface ; 

 while in the second there would be a natural di'ainage. In the 

 third case the subsoil would drain off the moisture beneficial to 

 the land ; while in the fourth the necessary moisture would be 

 retained. Furthermore, many subsoils contain ingredients that 

 the surface wants ; and by a judicious mixture of both, the last 

 would be greatly improved. 



Considerable areas of the land coloured on Jukes' Geological 

 Map of Ireland as Lower or Cambro-Silurian are semi-waste and 

 could be increased in value two, three, or four fold. I am ac- 

 quainted with some such lands, on which about £8 an acre was 

 spent in draining, liming, and tilling, thereby raising its valua- 

 tion from three shillings to between twenty and twenty-five 

 shillinofs. 



