2 QUARTERLY JOURNAL. 



even when they cannot be turned to account directly in the culti- 

 vation of the soil. .|i 

 Under the influence of these considerations, and others of mij, 

 nor importance, which it is unnecessary to state, I propose to giv ■ ( 

 first of all a recapitulation of the geology of New-York, with ; 

 view of applying all the facts which bear upon agriculture to it . 

 illustration. For the convenience of description, I shall pursu, 

 the plan adopted in the geological reports, namely, that of d( ; 

 scribing the rocks in the ascending order ; and this will lead me 1 t 

 speak of them in the order of the districts which I have alread.; , 

 briefly described, and into which the state has been divided.* 



The six districts coinciding nearly with six groups of roclsi /, 



each of these groups respectively imparts to the overlying scq 



some of its distinguishing characters, or in a good measure mafc^ J 



it what it is. Modifying influences, however, independent of t 'I 



geological formation, have done something as diluvial ortrai,| 



porting agents, by which soils originating and formed at a distanj,! 



have been brought to and distributed over adjacent districts. Sf^; 



it will be found on examination that the underlying rocks h^ 



given a stronger character to the soft materials than has usuaj, 



been supposed, leaving out of view some areas in every disti<((i 



where drift has lodged in deep beds. 1 1 



In estimating the amount of soil furnished by groups of roc ,| 



we are necessarily obliged to observe the nature of the masj^, 



Many of the shales and slates, and they occur in almost ev f 



group, disintegrate rapidly, the action being favored both by wjr 



and frost: the first, penetrating between the lamincc, partially sef 



rates them ; and in some instances no other agent is requirec 



eff-ect an entire destruction of a stratum, especially where weti 



and drying alternately occur. In other cases, the assistanw 



frost is required to eff-ect a complete reduction of the straff 



soil. • 1 u 1 



Limestones are liable to a constant loss of material by sol 

 properties of rain water, which holds carbonic acid in solutt 

 and this operation is favored by a rough or uneven surface, w 

 the water stands for a time. On a polished surface, the actio 

 water and other agents is very slow and inconsiderable even i 

 the lapse of several years, as is proved by the durabih ty_ot 

 • See article Temperature, No. 2, vol. I. 



