360 Dr Davy's Agricultural Discourse. 



qualities of those varieties of soils which are most strongly marked ; 

 and, lastly, I shall venture to offer a few remarks, as suggestions, on 

 the admixture of soils and their treatment, with a view to ameliora- 

 tion in certain instances in which there are glaring defects. 



On this occasion, as on the former, I shall have need of, and 

 have to ask your indulgence, for the subject I am entering upon is 

 a large and difficult one. I have not the advantage of a practical 

 knowledge of it ; the views, the information I have to offer, are 

 more of an abstract kind than practical men commonly like, or are 

 disposed to confide in ; but being founded, as I believe they are, on 

 scientific principles, and addressed, as I trust they are, to a scienti- 

 fic audience, that is, to an assemblage of well-informed men, con- 

 vinced that science is essential in agriculture to promote its improve- 

 ment, and give it its highest degree of perfection, I am confident I 

 have not to ask your indulgence in vain. 



Commonly, there is a certain connexion observable between the 

 geological structure of a country and its soils. In a large number 

 of instances this connexion is most intimate ; so that the rocks con- 

 stituting the hills and mountains being known, the soils of the plains 

 and valleys may be predicated with considerable accuracy ; and for 

 this obvious reason, that the latter, by a process of decomposition 

 and disintegration, are derived from the former. This is remark- 

 ably the case in primitive countries, in which the existing soils ap- 

 pear to be formed almost entirely by the processes alluded to. Oc- 

 casionally, however, it is otherwise; there are countries in which 

 there is no immediate relation, at least of dependency, between the 

 soils at the surface and the strata on which they are incumbent, the 

 soils not being derived from the rocky strata on which they rest. 

 This is strongly marked in the instance of tertiary geological forma- 

 tions, those in the history of our globe of recent origin, formed of 

 the detritus of older rocks, brought down by rivers or thrown up by 

 volcanoes, deposited in the ocean; there modelled by currents, va- 

 riously consolidated and altered by additions of materials which they 

 there receive, ultimately to be raised, by forces acting from below, 

 into the common air, to become islands or parts of continents, ac- 

 cording to situation. Some of the most fertile parts of the earth 

 are of this description ; the majority of the West India Islands are 

 such, and Barbadoes eminently so. 



As regards the interests of agriculture, what I have just adverted 

 to may be held to be a great advantage, as I shall, farther on, have 

 an opportunity of pointing out ; but as regards the study, the de- 

 scription, the comprehension of the soils of a country, it adds vastly 

 to the difficulty, presenting, as it does, a subject of almost incalcu- 

 lable complication, instead of one of simplicity and uniformity. 



In my preceding discourse, I took a hasty glance at the geology 

 of Barbadoes, of its two parts so well marked by contrasts, — the 

 smaller portion, formed of steep hills and descending valleys, con- 



