Botany and Zoology. 129 
cracks are more ested in length, but less open. ‘The shell is about 
the twelfth of an inch thick; and now appears more like lignite than 
any more recent vege matter. -Of course nothing of the kernel, 
or true seed, remained. In its place there are some particles of black 
vegetable be pias is with some powdery marl—all which do 
not near fill the present cavity. 
Though my labors in excavating marl of different kinds during many 
years, and sive much more ex xtended personal examinations elsewhere, 
ave giv € opportunities rarely enjoyed by others for seeing and 
gubering fossil specimens from their localities, I. make no claim to the 
character of a scientitic investigator of pe subject, Therefore, I do 
not Sa whether (as I infer it is) this nut is an extinct species—or 
whether the like has been found befor 
This marl, bordering the Pamunkey river, has peculiar characteris- 
ties, and also has tare value asa manure. ‘The fossil remains are gen- 
erally much decayed. Among the kinds Ss most common, are shells of 
Ostrea selleformis and Cardita planicosta, either of which sufficiently 
identifies the marl with the eocene. Some other fossils are either new, 
or very rare, at least to my observation. Among the most rare isa 
fragment of a spine of an extinct Echinus, which is eight inches long, 
and more than three quarters of an inch in diameter, where thickest. y 
Comparison of the size with the species of the largest spatttliens known 
to me of recent Echini, this extinct species must have had a very large 
body, beset with spine 33 feet long. Ihave also found smaller fragments 
of these species in the eocene marls of Coggin’s Point, James river, Va., 
and of the Santee in South Carolina. ‘The flutings of the surface of 
these spines are beautifully regular ; so as to seem like delicate artifi- 
cial carved work. 
Lignite is often found in this eocene marl, I have two specimens of 
impure amber which were found in this kind of marl, though not in my 
own diggings. One of these was broken from a solid mass which was 
Said by the person who found it to have been nearly a foot in diameter. 
Marlbourne, Va., July 4, 1849. 
2. Synopsis Generum Crustaceorum Ordinis ‘*Schizopoda” J. D. Dan 
elaboratus, et Descriptiones specierum hujus ordinis que in Orbis erra- 
tum circumnavigatione, Carolo Wilkes e Classe Reipublicee Faederate: 
Duce, auctore lecta:.—(Pars |. 
Orpo II. CRUSTACEA SCHIZOPODA. 
Crustacea Macrourorum pullos affiliantia, branchiis sive extern 
—- thoracis abdominisve pertinentibus, sive obsole etis; pedibus eee 
irameis palpo valde elongato; agitlipedibon pedes sequentes spe 
italeaitantibiie 
Tribus I, DIPLOGPODA. 
Pedes thoracis biramei, palpo natatorio, nulli prehensiles. Cara- 
pax Sephateroeadieth plerumque 4 segmento ote non Fass 
discreto, ; 
VW 
F 3 ie 
Seconp Serms, Vol. IX, No. 25.—Jan,, 1850. 
