grasses not being what is termed scourging plants, especially {318} when not allowed to seed—to the complete cover of the ground by the leaves—to the quantity of root which dies annually—and to the mould thrown up by the red earth-worm, renovating the surface, and partly covering the moss and decayed leaves and old bulbs. It is a curious fact, that, under pasturage, fertility should increase in Britain and diminish in Australia. An uncropt deep cover of grass appears necessary to shelter the vegetable soil-matter during the arid heat, and even to protect the roots from being burned out, in the latter country. And the manure of cattle, instead of being covered by the luxuriant herbage before it is desiccated, and enriching the soil as in England, is, in New South Wales, under the powerful sun and arid air, quickly reduced to dust and dissipated. The fertility of soils may also be quickly increased, and the vegetable cover thickened almost to any extent under tillage, by first rearing a quantity of large growing annual vegetables, and when nearly full extended, burying this green vegetable produce in drills, resowing the ground immediately with another fast growing kind, and proceeding thus continuedly. The influence of birds in enriching forest soil, is exceedingly limited, and is chiefly perceptible, not in continued forest, but in some detached portions or {319} clumps of park trees, which colonies of rooks or other large birds frequent. Of the natural grass which Mr Cruickshank states succeeds in woods to the original heaths, and which he describes as affording such excellent tender food for cattle, we can only say, that either the woods must have been unprofitably thin, and the trees naked, or that he has completely mistaken the quality of the herbage. The grass of woods is unhealthy food for cattle, and generally not relished, being rendered unpalatable and noxious by the resinous and bitter droppings from the tree leaves, and by the bitter and nauseous juices generated in the soil by the roots of trees, which the herbage roots draw up. In dry soils, there is sometimes an accumulation of whitish substance within the ground, around the roots of trees, which some refer to excrementitious deposit[61], but which, we think, is rather the produce of a subterraneous vegetable, of the nature of a fungus or mould. Wherever this has increased to a considerable extent, we believe old forest ground will be found of great fertility. {320}