218 CALCAREOUS MANURES— APPENDIX. 



miocene be added, which, though not certain, I believe to be eocene, 

 there would be 69 feet. And if this and the two other lower clay strata 

 be deducted, there will still remain 45 feet of strata exposed, all rich in 

 green-sand, and of it 9 feet very rich also in sulphate of lime or gypsum, 

 and 1 1 feet moderately rich in carbonate of lime. Such a deposite is 

 well worth the exanjination of geologists and chemists, and the trial of 

 farmers. 



It was remarkable that at this place only of all the usual strata of all the 

 then known deposites of green-sand or eocene marl in Virginia, were found 

 exposed, the shells of the ostrea compressirostra — and below tide the other 

 before unknown and very thick and heavy ostrea; and that at this place 

 there has not been found a single shell of either the ostrea sellczformis or 

 cardita planirosta, the latter of which is so abundant through all other 

 known eocene deposiies, and the former in the calcareous eocene elsewhere. 

 These facts seemed to indicate (as well as the general dip to the eastward,) 

 that the strata at Evergreen are much more elevated than the same at 

 Coggins Point — and that by digging deeper, the lower and all the strata 

 of the former might be found at other parts of the known area (before de- 

 scribed) of the eocene formation. 



This inference added to other considerations caused to be sunk the se- 

 cond shaft above mentioned in the beach of Coggins Point, 130 yards dis- 

 tant from the first one, which by this time had been filled completely by the 

 sand driven by storms and high tides. The digging was made at a low part 

 of the bank, and which therefore did not show either the eocene marl or 

 the miocene, the former of which is seen in the higher bank at a short dis- 

 tance, and both together at the distance of a mile. The different strata 

 of the actual section at the new digging, taken descending from the top of 

 the bank, were as follows: 



1 foot, surface soil— gray loam, ancient alluvial deposite. 



7 feet of pale yellow clay, containing much coarse silicious sand. 



4 feet rounded or water- worn pebbles, of all sizes, from 4 inches through 

 to coarse gravel, held together by enough clay and ferruginous earth to 

 fill the interstices between the pebbles. None calcareous. 



2 feet of very thin layers of hard and gritty gray clay, alternating with 

 others of coarse ferruginous sand. 



2 feet of poor greenish earth, more than half the surface of the section 

 brown in spots, and indurated with oxide of iron. 



(Here should be, as elsewhere in the neighborhood, though absent at this 

 particular locality, either one or both, the miocene marl, (A,) and next be- 

 low the eocene calcareous marl (B) described in the preceding pages.) 

 (C) 9 feet of the ordinary upper layer of gypseous earth — green color, mot- 

 tled with spots of bright yellow clay, (or ochre,) and some other 

 spots of unctuous reddish brown clay. Very slight efflorescence of gyp- 

 sum on the surface. 

 (Z>) 3 feet of darker and nearly uniform color, almost black, from the greater 

 proportion of green-sand. This and the preceding, containing many 

 impressions of shells, but no .shells or fragments, and no carbonate of 

 lime. More efflorescence of gypsum, and also on next — 

 (Z>) 3 feet of same, except that some shells are seen — and increase in the 



next to level of river at common high tide. 

 (Z>) 6 feet of same (next below tide — ) the shells mostly cardita planicosta 

 — fewer of rz/f/je»-ea and corbula.. No ostrea or turritella. Small and 

 slender shark's teeth (so called) in perfect preservation, the points and 

 edges being as sharp as in teeth of the living animal. 

 (E) 15 feet bluish gray or lead-colored clay, (from 6 to 22 feet below tide,) 



