98 GEOLOGICAL REPORT. [Tl 144 



or muriatic acid ("spirits of salt''), it is not difficult for the planter 

 to obtain an approximate idea of the value as fertilizers, of most 

 of these marls ; especially as, in the majority of cases, the greater 

 or less abundance of shells is itself srmewhat indicative of the 

 amount of lime in the mass. When fresh and moist, its tint is usu- 

 ally bluish-gray, with white specks (being fragments of shells) and 

 glistening scales of mica (''isinglass") ; and when cut, if the mass 

 contains any notable amount of greensand, dark green, or almost 

 black streaks will be visible on the surface, which may be traced 

 back to rounded grains, from the size of a grain of rifle-powder to 

 that of a gumbo seed, with a smooth surface, and generally of a 

 flattened shape. Sometimes, however, the grains are so small as 

 to be perceived only by the aid of a ma<rniner. or by the general 

 tint of the mass. 



In searching for these marls in the region of occurrence indi- 

 cated on the map (by the bright green tint), it should be recollected 

 that, as has been stated, they generally undrclie the limestone ; and 

 that if they have been struck in wells on the ridges, they are 

 likely to be found at the same level, at. no great depth, on the hill- 

 sides. 



144. The marl at AVilhite r s (1131) showed the following compo- 

 sition : 



WILHITE'S ALA I! J.. 



Insoluble Sand anil Clay 73. IK I 



Potash 0.702 



Soda (detn. lost) 



Lime 6.315 



Magnesia 0.88G 



Brown Oxide of Manganese 0.050 



Peroxide of Iron 7.055 



Alumina 5.888 



Phosphoric Acid 0.04G 



Carbonic Acid, Water and Loss 5.640 



100.000 



This marl, while containing a large amount of potash, contains 

 at the same time so much inert matter, that it will not bear trans- 

 portation to any great distance, inasmuch as a "dressing" will 

 require a quantity greater in proportion as the active ingredients 

 are less. No overdressing with a marl like this will be likely to 

 happen. 



This is the only marl of this character wdiich T have thus far 

 analyzed, but judging from appearance, it represents very nearly 

 the marls of the lollowing localities : in Tippah, Kindrick's mill 

 (1131, Sec. 12), Ruckersville ; Braddock's (1131); Owl Creek 

 (1132); lowest stratum at Tippah Creek bluff, at Ripley (1132, 

 Sec. 13); Edick's place, S. of Ripley; blue marls on Ripley and 

 Molino road ; at Col. Berry's (1133), and at Lewis L. Nahors'. 



