1S36.] 



FARMERS' REGISTER. 



673 



matter in different localities, will be a work from 

 which much practical good may be derived. By 

 the light of such results alone, can the farmer be 

 safely directed in applying it to the soil, or be pro- 

 perly guided in distinguishing, between a mate- 



rial which is spurious, and one which will be 

 found salutary in its effects upon the land. 



The following results are to be looked upon as 

 approximate determinations, but will serve to il- 

 lustrate the composition of several varieties of the 

 marl: 



Composition of green sand (Eocene) marls 

 Doctor Corbin Braxton's, 



Walker Tomlin's, lower stratum, 



Conrad Webb's, 



Wm. H. Roane's, lower stratum, 



Tarbay, lower stratum, 

 Do. upper stratum, 

 Berkeley, 



Viewing these results generally, it is apparent, 

 that while in some cases the efficacy of the marl 

 would be ascribable in a degree to the calcareous 

 carbonate or sulphate present in large proportion, 

 in a great, many others the green sand ought to 

 be regarded as the chief, if not the only agent in 

 the effects. A dressing of many of these marls 

 to the extent usual in the application of the Mio- 

 cene shell marl wouid scatter upon the soil a pro- 

 portion of green sand, nearly as great as the ave- 

 rage quota which is at present in use in New Jer- 

 sey, and in the richer sorts, a much less proportion 

 would be necessary than it is customary to ap- 

 ply where the shells abound. 



We are struck, in considering the composition 

 of these marls, with the happy variety of consti- 

 tution which they exhibit, which, should there be 

 any specific action of the respective ingredients 

 on particular vegetables, which there is reason to 

 believe is the case with one (the gypsum,) will 

 the more completely adapt them to the variety of 

 crops to which the farmer would wish them to be 

 applied. 



Some caution will be necessary in distinguish- 

 ing the marls, containing a large proportion of 

 green sand, from dark greenish clays and sands, 

 which have sometimes been mistaken tor them. 

 These clays are always entirely destitute of fos- 

 sils; they have an astringent or copperas flavor, 

 and generally a strong sulphureous odor, though a 

 slight smell of this kind is also often observed in 

 the best marls. The occurrence of small shells 

 sparsely distributed and in a decomposing state is 



Vol. III.— 85 



Silica and alumina, &c. 

 Carbonate of lime, 

 Green sand, 

 Gypsum, 



Silica and alumina, 



Carb. lime and gypsum, a trace, 



Green sand, 



Silica and alumina, &c. 

 Carbonate of lime, 

 Green sand, 



Silica and alumina. &c. 

 Carb. lime, 

 Green sand, 

 Gypsum, 



Silica, alumina, Sac. 

 Carb. lime, 

 Green sand, 



Gypseous earth containing from 6 to 

 10 per cent, of gypsum, and from 

 10 to 15 per cent, of green sand. 



Silica, alumina, &c. 

 Green sand. 



50 



10 



38 



2 



60 



40 



30 



45 

 25 



60 

 4 



46 

 3 



40 

 3 



57 



50 

 50 



very frequent in the good marls, though an almost 

 total absence of shells is sometimes observed. 

 ITine sparkling scales of Mica, (not gypsum, as 

 supposed by some.) are generally present in con- 

 siderable proportion, and have led those who spec- 

 ulated upon the action of the marl, to ascribe a 

 large part of its efficacy to the supposed sulphate 

 of lime or gypsum contained in it. To distin- 

 guish a marl of this kind from the dark blue Mio- 

 cene marl, a slight attention to the embedded fos- 

 sils will be sufficient. The saddle-shaped oyster, 

 characteristic of the Eocene, and never found in 

 the latter deposite, would at once determine the 

 bed in which it is found to be of the former de- 

 scription — while the common scallop or clam, 

 which is never seen in the Eocene, would indi- 

 cate the Miocene character of the bed in which it 

 lies. 



In concluding what I have to say upon this im- 

 portant, topic, I may be permitted to throw out the 

 suggestion, that should the deposite of which I 

 have been treating, be found as extensive in its 

 range and as useful as a manure as here anticipa- 

 ted, the districts of the state contiguous to its wes- 

 tern limits, as well as the region in which it oc- 

 curs, might be expected to reap important bene- 

 fits from its employment. Parts of Henrico and 

 Hanover, and the lower part of Louisa, in which 

 no marl exists, would be sufficiently contiguous to 

 the Pamunkey deposite to avail themselves pro- 

 fitably of its use, and when the projected improve- 

 ments in, this region of the state shall present 

 cheaper and readier means of transportation to 



