CALCAREOUS MANURES-APPENDIX. 225 



heard of but few other applications in Virginia, other than those made on 

 Coggins Point farm, and of none with different or better certain effects. With 

 the help of surplus carbonate of lime in the soil, (furnished by nature or by 

 previous marling or liming,) 100 bushels of this earth, averaging in 

 strength the ingredients of these specimens analyzed by Professor Shepard, 

 would furnish nearly 5 busliels of pure sulphate of lime (gypsum) ; and 40 

 bushels to the acre would furnish 2 bushels of sulphate of lime. Not one 

 of these specimens contained any gypsum visible to the eye ; and but one 

 specimen (number 9) contained any visible sulphuret of iron; and therefore 

 these ingredients may be fairly supposed to be at least as abundant in the 

 earth dug in any considerable operation. What the green-sand or any 

 other ingredients may do in addition, I pretend not to estimate. But so 

 far as I have learned from my own experience and all known experience 

 of other persons, the whole operation of this earth, when used alone, is 

 precisely of such kind as I would anticipate from gypsum, though yielding 

 more of benefit in measure and value. Nor should I therefore be under- 

 stood as placing a low estimate on the value of the effects produced. Since 

 seeing the effects this year, and especially since having formed the opinion 

 that the upper and exposed parts (most generally used formerly) are com- 

 paratively worthless and should be avoided, I count on much benefit being 

 derived from this manure, and am desirous that it shall be largely used ; 

 as my son and partner, and the sole director of our farming, proposes to 

 do for the next year's growth of clover. Still, I am now as far as ever from 

 believing in or expecting such great and regular benefit as would be in- 

 ferred to be certain from views and statements which rest upon other au- 

 thority. 



It may not be useless to note another point of recent resemblance be- 

 tween these two manures, both of which seem so capricious and uncertain 

 in operation in general. This year (1842) the applications of the green 

 earth on the Coggins Point farm, whether made in the beginning of the winter 

 preceding, in March, or in the beginning of summer, have acted more quick- 

 ly and powerfully than any known before. This I had ascribed to the earth 

 being mostly obtained from deeper excavations. But I have lately heard, 

 from Messrs. Hill Carter and John A. Selden, both extensive and experi- 

 enced and successful users of gypsum, that they have never before known 

 the good effects of that manure to be so remarkable as in all their applica- 

 tions of this year. 



(d.) EOCENE GREEN-SAND MARL. 



Except in the lower stratum exposed in the pit recently dug at Ever- 

 green, this peculiar valuable kind of marl has not yet been known in 

 Virginia elsewhere than on and near the borders of the Pamunkey river; 

 though there can be but little doubt that this or other eocene deposites are 

 to be found elsewhere than within the limits here stated of the now known - 

 localities. It is more than probable that other rivers cut through and ex- 

 pose some of the eocene as well as miocene deposites ; and that deep 

 diggings would reach them also in the intervening high lands. The 

 Pamunkey eocene marl is seen first, or most eastward, at Liberty Hall, 

 (Mr. Waring's fai-m,) in King William county; and it is found on nearly 

 every farm above, to South Wales, in Hanover, the farm of Mr. William 

 F. W'ickham, just below the junction of the North Anna and South Anna 

 rivers, and on the farm of Mr. Williams Carter, across the Pamunkey, in 

 Caroline county. This distance in a straight line is about 28 miles ; and 

 the very winding course of the Pamunkey serves to make the exposure 



