Association of American Geologists and Naturalists. 337 
sembled minute wrinkles, something like the impression left on soft 
clay by pressing a file on it. No medullary rays or growths could be 
discovered on the transverse sections of the trees. 
All the specimens observed had part of the bark converted into a 
black carbonaceous substance. Judging from the disposition of the scars 
on several of the specimens found, there must have been at least three 
species. This was shown on a drawing; and Dr. O. exhibited a mod- 
el, quarter the natural size of the smallest stump excavated. A portion 
of one of the roots of the largest one was also laid before the Associa- 
tion. The general character of these interesting specimens was deter- 
mined by the form of the scars, being longer horizontally than vertical- 
ly, and the absence of flutings. In the bed of Big Creek, fifteen feet 
beneath the roots of the trees, is a seam of coal supposed to be from 
three and a half feet to four feet thick. Almost immediately over 
them is a layer of sandstone, and over that an imperfect seam of coal. 
The top of the fossil tree is about fifteen feet beneath the level of the 
bank of Big Creek. 
Dr. Owen supposed from the present position of these trees, that they 
have been quietly submerged and now occupy the spot where they ori- 
ginally grew. 
A more detailed description of this locality of fossil palm trees will 
probably appear hereafter in this Journal. 
Dr. C. T. Jackson read a report on the organic matters of soils, 
and exhibited specimens of them and their characteristic salts 
and compounds. 
He demonstrated the complex nature of mould or humus, and proy- 
ed that only refined and exact analyses would show the causes of fer- 
tility and barrenness in soils. Several cases in point were cited, and 
among others the analysis of three soils; one of which was almost bar- 
ren; the second was moderately fertile ; while the third was remarka- 
bly productive and had been cultivated for nearly one hundred years. 
In these three soils the relative proportions of organic and mineral mat- 
ters were precisely the same, insomuch that it was supposed at first 
that they were all taken from the same spot; but a more refined anal- 
ysis showed a very marked difference in the condition of the organic 
matters, and to this difference, imperceptible to an ordinary or crude 
analysis, the difference in fertility was owing. 
The organic matters formerly confounded under the names of ulmin, 
geine and humus, are numerous and very different in their chemical 
nature, varying in different soils and producing various degrees of fer- 
tility. 
Vol. xiv, No. 2.—July-Sept. 1843. 43 
