228 CALCAREOUS MANURES— APPENDIX. 



The green-sand stratum (brownish color) of 7 or 8 feet above the water 

 was' not analyzed ; but, as at all other places on this river, was evidently 

 very poor in calcareous matter. 



On the land of Mr. George W. Bassett, Hanover, about 5 miles below 

 Newcastle ferry, the marl appears rich and of more homogeneous texture 

 and uniform appearance than generally elsewhere. Yet it is variable, and 

 on the average is poor in calcareous matter. However, this marl, which 

 has been largely used by Dr. Corbin Braxton, water-borne to Chericoke, 

 8 miles below, has been wonderfully efficacious. Still it has not been used 

 at all, or considered worth being applied, by its proprietor. Specimens 

 analyzed at different times showed the following proportions of calcareous 

 matter : 



Stratum a few feet above the level of river, 100 grains contain- 

 ed of carbonate of lime, - - - - - - 10 grains. 



And green-sand (supposed,) - - . - - - 35 

 Another (furnished and analyzed in 1840) carbonate of lime, 11 



And green-sand, 27 



Another, from different part of same bank, carbonate of lime, 45.50- 



This body was examined personally by the state geologist, and his esti- 

 mate of its contents of carbonate of lime and of green-sand was 34 psr 

 cent, of each. 



Over this marl is a regular stratum, perhaps 5 feet thick, of the olive 

 earth. The marl descends to the level of the river, and therefore the green- 

 sand earth below is not here visible. 



In the river bank of Northbury, in New Kent, one of the farms of Mr. 

 Conrade Webb, the green-sand marl presents the usual appearance, and 

 is overlaid by the olive colored earth. To my eye this marl was rather , 

 poor in the calcareous ingredient, and, as Mr. Webb supposed, in use was 

 often adulterated by the carelessness of overseers and laborers, by admix- 

 tures of the worthless olive earth. Still, the application as manure has 

 had very good effect. A large quantity of this particular body has been 

 dug and used ; but it has since been abandoned, because of the greater 

 value of and more convenient access to other more recently discovered 

 beds, which will presently be noticed. At Northbury, as Professor Rogers 

 supposed and reported in '835, "the precise point was determined at 

 which the eocene first makes its appeai'&nce above the water line" of the 

 Pamunkey. But it has been since found at Mv. Waring's farm, about 4 

 miles lower, as well as at Waterloo, another part of Mr. Webb's estate, 

 about two miles lower than the first diggings at Northbury. 



By using the borer in low places, but where no sign of marl was visible 

 on the surface, Mr. Webb has since discovered the eocene marl which will 

 be next described, at various points in a line stretching through the middle 

 of his large estate, and furnishing a convenient supply to each of the three 

 farms. At several distant points, large pits have been dug, which are sunk 

 from 16 to 20 feet deep in the solid marl, without reaching bottom or show- 

 ing any change of the lower of the two kinds of marl. The pits are work- 

 ed quite dry ; but no marl having been dug for some time before my visit 

 (May 1842) the pits were then all full of water to the brim, and there was 

 but little opportunity to examine the marl, except at the upper edges, and 

 in the heaps still remaining unspread over a part of one of the fields. 

 However, Mr. Webb had before selected and kept for me, a^ my request, 

 fair specimens in two large lumps of marl from one of the largest and 

 deepest pits, from which my anal)'^ses were made. The one, a specimen of 

 the upper 8 or 10 feet of depth, is full of large fragments of shells, gene- 

 rally very soft and much decayed, and with very few whole shells, except 



