210 CALCAREOUS MANURES— APPENDIX. 



at its south-western extremity, Spring Garden, and thickest at the north- 

 eastern, Neston and Evelynton. At Coggins Point, where traced along the 

 face of the river chff continuously for more than half a mile, it is usually 

 six feet thick, never more than eight, and never less than four feet, except 

 where terminating. The general and almost uniform color is a pale 

 dingy yellow. The few shells remaining are not perceptible without 

 careful observation, and the Whole mass, when dug down for use, is 

 scarcely distinguishable from many common and barren sub-soils, or clay 

 river cliffs, of like color. Two thin but continuous and separate layers of 

 almost stony hardness extend through the v/hole bed. These contain from 

 85 to 90 per cent, of carbonate of lime, and may be burnt to excellent 

 quick-lime for cement. The marl intervening with these hard layers is simi- 

 lar to them in color and general appearance; but is quite soft and mellow 

 in handling, and in that respect differs from all other known marls. The 

 very uniform calcareous proportion of this part is^about 53 per cent. ; and 

 taking an equal section of the whole thickness of the bed, and with the 

 greatest care to obtain a fair average sample, the strength in carbonate of 

 lime was found to be 62 per cent. This is far less of calcareous matter than 

 is contained by many miocene marls which show less effect than this as 

 manure. But besides its calcareous matter, this eocene marl has some little 

 gypsum, some kind of saline matter which cattle are fond of licking, (be- 

 lieved to be sulphate of alumina,) and some amount of the granules of " green- 

 sand" — and more of this than most of the miocene marls. The other 

 earth of this marl is mostly of yellowish clay, and composed more of argil- 

 laceous than silicious matter. I confess that all these additional ingredients, 

 together, do not seem to me sufficient to account for the superiority which 

 this marl exhibits as manure. 



Though this peculiar kind of marl was so early known, and its value 

 appreciated, and, though it underlies the whole of Coggins Point, yet it is 

 covered there so deeply by the overlying earth, and is therefore so difficult 

 to work extensively, and, moreover, is so distant from the main body of 

 the farm, that this has not been applied to more than 65 acres, out of 

 some 700 marled on that farm. Other proprietors have elsewhere made 

 much more extensive applications of this marl. The peculiar effects of this 

 kind of marl were tested with the most accuracy by Messrs. Collier H. Minge, 

 then of Walnut Hill, and Hill Carter, of Shirley; both of whom used this 

 marl from Coggins Point, water-borne to distances of 12 and 15 miles. 

 Though the marl was given to them, (in the bed.) it was yet very costly in 

 the labor of digging and transportation ; and therefore they used it with 

 strict economy, and carefully estimated the results. But highly as they 

 both thought of, and have reported the effects,* in comparison with either 

 lime or miocene marls, the expense and trouble were so great, that it is 

 now considered by the most judicious farmers on the tide water rivers, that 

 they can better afford to buy stone-lime, at its present low price, (8 to 10 

 cents the bushel,) than to transport marl of any kind by water 



Since the foregoing pages were written, I have learned of two farther 

 exposures of this body of eocene marl. One is four miles north of Eve- 

 lynton, (in Charles City county,) where the marl was reached and pene- 

 trated by the digging of a well in 1814. At about 30 feet deep, after 

 passing through the marl, and a layer of rock, water was reached, which 

 rose to the top of the well, and continues to flow over, forming the only 

 Artesian well known in this region. The other locality is in Henrico 

 county, on Turkey Island creek, its eastern boundary, and about 8 miles 



* See Farair^rs' Register, vol. v., pp. 1S9, 247, 511. 



