I noticed a communication on Western Prairies in your valuable work, from the pen of an able writer, "Why are they not Forests?"

I wish to differ from him a little; also from the popular opinion of the day, or, at least, other reasons worthy of note can be submitted in addition to his, that have some bearing on the cause. In the first place, I have resided on the beautiful Western prairie of Iowa for the last seven years; and as my mind has often been deeply impressed with the sublimity and beauty of the works of nature in this particular, and being placed in a position by my fellow-citizens, where it becomes my duty to inform myself in agricultural pursuits, both in the examination of the soil and its products.

I have noted the soil of different prairies - their locations, their different qualities; and have noted particularly the great depth of soil, caused, no doubt, by some great freak of nature, as the soil of the timber land, in many instances adjoining was not one half the depth, and of a heavy clay soil, while the prairie was of a loose black loam, often quite sandy, even small pebbles, that could not have been produced by fire. It is said, a cause has its effect. We find some parts of our Western prairies have been settled for the last twenty years; and interspersed with these settlements we find thousands of acres of land in the hands of speculators uncultivated, and where the prairie fires are not permitted to spread; still, we find neither sprout nor shoot of any kind, except on a kind of brush land that is distinct from the clean prairie, which often extends as far as the eye can reach, the grass partially kept down by herds of cattle from adjoining settlements.

There is no doubt but that seeds of different kinds often drop on these prairies by birds or strong winds from the timber, but by some cause they do not take root. It seems the soil is not adapted to the growth of timber until cultivated. We find the prairie in this State to be high rolling land; the timber land to be that portion skirting the rivers or streams, generally of a thin shallow soil, except the bottom land between the bluff and the stream, and in many instances this portion to be void of timber, particularly that part that is of a deep and unnatural soil. Now this is evident to my mind, that the majority of the prairie land has been prairie from the time of a great flood, or from some convulsions of nature, and has remained so ever since, the decree of an all-wise Providence for the benefit of poor frail man, although such has not been the ultimate result; for, in consequence of the ease in bringing forth the products of this loose loam, and the abundance of the crops, it has naturally produced indolence in our agriculturists, after producing a crop of corn on these prairies, say twenty years on a piece of land successively, which can be done, and still the soil retains its color, and its richness to some extent, and is much preferred for, and considered better adapted for fruit trees, or for planting groves on.

It is evident that the prairie soil is largely impregnated with magnesia and lime; so much so in some locations, that lime is no benefit as a stimulant. I have often reflected in my mind, the number of times it would require the fires to run over these prairies to create a soil from one to two feet deeper than the adjoining soil of the timber, as we often find it; and we often find the soil varying; sometimes the sand on top, sometimes the the loam, on a rich clay of a dark color, being evident it came there promiscuously.

These are my observations. Use them, or a part, as you think proper.

[ We had no idea, when we published the first article on the Prairies, that it would lead to such interesting developments. We have now had three interesting and valuable articles on the subject, all of them from parties who have spent much time on the prairies, and one of whom has examined them as a man of science. All three in the main agree, but differ not a little from most travellers and novelists. In solving the question, "Why are the Prairies not Forests?" there will naturally be a difference of opinion, since the cause is not apparent. Indian tradition would lead us to believe that the prairies were burned over many hundreds of years before the white man took possession of this continent. This fact, with its results, will form a very interesting subject of investigation for our correspondents, who, we hope, will send us still more material for history. - Ed].