232 



of Middletown. These localities being near the northwestern 

 margin of the formation, where only the lower portion of the 

 greensand, adjacent to the underlying blue clay exists, the material 

 contains, as in nearly every similar locality, but a moderate pro- 

 portion of the green granular mineral, in which, as we conceive, 

 the chief fertilizing power resides. 



The hills here referred to, terminating on the farm of Mr. 

 Conover, near the Dutch Church, consist of the ferruginous 

 yellow sands, immediately overlying the greensand, overlaid by 

 the brown ferruginous conglomerate which constitutes their sum- 

 mits. Greensand, therefore, occurs in places, beneath these hills 

 and around their base. It is generally replete in the green 

 mineral, and is of excellent quality, having been used in the 

 neighbourhood since the first discovery of its fertilizing eifects. 



At Conover's, near the Dutch Church, we are in the midst of a 

 highly fertile marl tract. The country is rather flat, or gently 

 undulating, and extensively intersected by shallow valleys of de- 

 nudation, or by meadows which are furrowed out down to the 

 marl stratum, and in some cases twelve feet into it. 



Analysis of the Marl, from the farm of Jacob Conover, Freehold 

 township, Monmouth county. 



Composition. — In 100 parts: 



Greensand, - - - 85 



Clay, - - - - II 



Quartzose sand, - - - 4 



100 



The amount of potash which this marl contains, deducing it 

 from that of the greensand, is 9-7 per cent. 



The soil is mostly a loamy clay, sonietimes sandy, and not 

 often more than thirty feet above the top of the marl. Upon the 

 marl lies a sandy stratum, containing a trifling share of the green 

 particles and much ferruginous matter, which in some cases, by 

 filtering down, has produced a change on the upper part of the 

 marl bed to the depth of a few feet, dissolving out the shells and 

 replacing them by oxide of iron. The thickness of the marl bed 

 is not known, but perforations twenty feet deep have not pene- 

 trated through it. Its general aspect when moist is a deep blue, 



