(Vol.. v., No. 118.-'
��ratber large possible errors of the rosulls of such ex- periments; and for tlial purpose I used tlje material nearest at hand. In order, however, to prevent anj further misapprehension, I desire to Ha; thai I fuJl; concede Dr. bturtevant's claim to priority ; although, owing to the fact that the bulletins of the New- York station are to be had at first hand only through the press of that state, I was not aware, at the time my results were first published (Bulletin No. 3 of the agricultural experlmenl^tallon o[ the University of Wisconsin, June, 1864), that he bac] anticipntec) inc by three or four weeks.
I fully appreciate bis remarks regarding the value of recognition, on the part of science, of scieutiflc work at experiment-stations, and slioulJ regret ex-
��cultural science is too wide, and the workers in II far too few, to justify any professional jealousy.
H. P. AuiiSBY, UMUHm, Wit., April 30.
��TeTtiBi7 pbosphatea in Alabama.
Since the publication of my two notes in Science last year, respecting the occurrence of phosphates in the cretaceous formation of this stale, we have found that they occur also at nl least two distinct horizons in the tertiary formation.
This formation In Alabama shows the following well-marked subdiyisions, given In descending or-
��also on ilie Alabama River, at Giillelle's and Block's Bluffs, and crops out between the two rivers in Ibe lower part o( Mnreiigo county, where its presence is Indicated by limy spots, or ' prairies,' of very great terlilily, "Hiis marl contains also a very considerable perceutage of greensaud, and, apart from the phos- phoric acid which it contains, would have become a valuable fertilizer.
The other phosphate- bearing horizon is in the lower or Jackson division of the white limestone.
At the base of the orbitoidal limestone which forms the greater part of the bluS at St Stephen's, Mr. LangdoD finds a bard ledge of rock holding Plagiostoma dumosa, and immediately beneath this, and extending fifteen feet down to the water's edge, a glauconitic marl holding numerous nodules or concretionary masses of phosphate of lime, — a:i occur- rence ijuite similar to that of the nodules In the cre- taceous beds at nambure In Perry county, described
�� ��'. Langdoii s analysis of the greenaaiid
��tains 22.0&% of phosphoric i
On the opposite side of the river, in Clarke county, similar materials have been collected and analyzed. A greenish glauconitic sand, occurring some three or four miles north of Coffeeville, contains 1.10 % of phospboric acid.
Fifteen or twenty feet above this marl, there is k yellowish-brown loam holding soft yellow nodular masses varying in size from one inch to eigbleen inches in diameter, and containing 2,74 % of pbot- phoric acid. This loam Is probably formed by the (tlsintegration of the Jackson limestone, the age uf
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��IrilwcHxIi of iliignr.l.
��The Upper of these two divisions consists mainly of limestones, called throughout the country, and by Professor Tuomey, the ' white limestone.'
The lower division consists of sands and clays, which make up the greater proportion of llie thotl- ■anil feet or more of the strata of this group; but in- letstmtified with these are five or six, and perhaps a greater number, of beds holding marine shells, the aggregate thickness of which may perhaps be ^veii at a hundred feet,
Mr. D. W. Langdon, jun., of the state geological survey, while on a collecting tour for Mr. T. H, Al- drich, made the discoveries to which this note is lu- tend»l to call attention.
At Nanafallo, on the Tomblgbee River, there is a remarkable series of beds, over fifty feet in thickness, made up almost entirety of the shells of a small oysl«r (Gryphaea thirsae). At intervals throughout this thickness are projecting indurated ledges, hold- ing the same shells, but forming a tolerably compact ruck. A specimen from one of these hard ledges, one or two feet thick, has been analyzed by Mr, Langdon. and found to contain 0.7% of phosphoric acid. Other parts of the Gryphaea beds may be similarly phosphatlc, but no analyses bare yet been made to nhow it.
This Nanafalla marl, which occupies a position nenrly in the centre of the lignitic subilivjfiion, occurs
��the stratum beins indicated by the specimen of Plsgi- □stoma dumosa which it contains.
Again : near Grove Hill, in Clarke county, one of my students. Mr. S. S. Piigh, has collected a number of phosphatic nodules which contain 10.4S%of phos- phoric acid.
Where the argillaceous limestones of the Jackson age form the surface, they give rise, in their disinte- gration, lo the rich limy or ' prairie ' soils wtaicb characterize my 'Lime Hills' region,' which occurs over a good part of the counUes of Choctaw, Wash- ington, and Clarke. It is more than iirobable that the exceptional fertility of the soils of this region is in great measure due lo the presence of these pboa- pbates. In the upper part of the while limestone (Vlcksbut^), I have not yet been able to detect onj' imusual proportion of phosphoric acid.
In this connection it may be interesting to note that Mr. I.. C. Johnson, of the U.S. geological survey, has traced the extension of the Alabama cretaceous phosphate beds into Mississippi, along the line point- ed out by me In one of my notes above referred to. The occurrences In Mississippi are quite similar b those already described in this slate.
Eugene A. Suitb^]
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