July 25, 1884. | 



SCIENCE. 



79 



The material from this horizon, which has been 

 examined by me, consists, 1°, of marls — either cal- 

 careous clay marls, or light chalky marls — composed, 

 in the main, of carbonate of lime (the few analyses 

 of these marls which have been made, show an aver- 

 age content of about five per cent of phosphoric acid ; 

 they occur across the whole width of the state, and 

 are, in many instances, in very good condition for 

 spreading upon the land: a marl of this kind at 

 Coatopa has already been used with very fine results) ; 

 2°, of limestone rock, usually crystalline, hard, and 

 sometimes sandy, but occasionally soft and crum- 

 bling; in one locality the calcareous matter has been 

 leached out, leaving a porous sandstone: this lime- 

 rock, which is the Kipley limestone, holds from ten 

 to fifteen per cent of phosphoric acid, and extends 

 entirely across the state: the aggregate amount of 

 phosphoric acid contained in it is enormous; 3°, 

 of nodular or concretionary masses of phosphate of 

 lime, and nuclei or casts of gasteropods, bivalves, 

 nautili, baculites, etc. ; these, wherever examined, 

 appear to be nearly pure phosphate of lime, but are 

 found in comparatively limited quantities : not more 

 than half a dozen quantitative analyses have yet been 

 made of the phosphatic material from these beds ; but, 

 in making the qualitative tests, I have always used 

 equal quantities of the different substances, and have 

 thus been able to form some estimate of their com- 

 parative value. 



The outcrops of the phosphatic beds occurring at 

 the base of the rotten limestone, already described 

 in a former letter, pass near the following places, 

 — Pleasant Ridge, Eutaw, Greensboro, Hamburg, 

 Selma, Prattville, Wetumpka, Tuskegee, and Society 

 Hill, — while the beds now described above, outcrop 

 along a line about thirty miles south of the former, 

 passing through or near the following places, — Liv- 

 ingston, Coatopa, Moscow, Dayton, Prairie Bluff, 

 Minter Station, Fort Deposit, Union Springs, Flora, 

 etc. ; the one line of outcrop being along the northern 

 border of the 'prairie region,' the other along its 

 southern border. 



It is, further, an interesting fact that the upper beds 

 of the rotten limestone itself are phosphatic. I ex- 

 amined recently the outcropping limestone from 

 Livingston for six miles northward, and in every case 

 found it to be more or less phosphatic ; and in a few 

 places I found nodular phosphates in small quantity. 

 In other localities, as at Boligee, and between New- 

 berne and Uniontown, at a distance from either 

 border of the rotten limestone, occur phosphatized 

 nuclei of shells. I have not yet had the opportunity 

 of examining the strata at these places, and cannot, 

 therefore, say whether or not the phosphates are con- 

 fined to these nuclei, but am inclined to think that 

 phosphatized strata occur at intervals through the 

 whole thickness of the rotten limestone, as well as at 

 its base and summit. 



Whether any of these phosphates may be profitably 

 shipped to distant points or not, it is certain, that, in 

 the phosphatic marls and greensands, our farmers, in 

 the ' prairie region ' at least, have the materials for 

 restoring the fertility of their soils at a comparatively 

 small cost. Eugene A. Smith. 



University of Alabama, July 12. 



Swarming insects. 



I am not a properly qualified reporter of scientific 

 facts, but the following observations have interested 

 me: — 



I sat on the doorsteps of 626 Euclid Avenue some 

 days ago, watching the ' Canada soldiers,' of which 



gnat-like looking insect I enclose a specimen. They 

 filled the air. They were absolutely myriads. The 

 north wind, I am told, brings them from over the 

 lake; but they are ephemeral, and their dead bodies 

 are almost as numerous on the pavements as their 

 live bodies in the air. 



As I sat watching their flight, my attention was 

 attracted to a singular smoke-like appearance on the 

 top of a tall elm which stood at the edge of the street- 

 curb. From the topmost branches of this tree rose 

 vertically into the air four or five waving, flickering 

 tongues of what at first looked like smoke. To 

 describe their peculiar lambent motion, I can think 

 of nothing better than the ' cloven tongues of fire ' 

 mentioned in the 'Acts of the apostles ;' or the darting, 

 flashing spires of the aurora borealis, only the color 

 was smoky, not fiery. I give a rude delineation. The 



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waving, playing motion of these smoky spires is sim- 

 ply indescribable. They would fade and re-appear, 

 wave back and forth as if swayed by the wind, mount 

 higher and higher, until sometimes one would leap 

 up twenty, thirty, or forty feet into the air. The 

 look was as if the tree was smoking, the thin wiry 

 columns of smoke streaming up into the sky. Closer 

 examination disclosed the fact that these pillars of 

 smoke in the evening twilight were really columns 

 of winged insects, but whether the ' Canada soldiers,' 

 or a smaller insect, I could not see; and inquiry 

 elicited the further fact that this phenomenon is not 

 exceptional. Perhaps it has already been noted in 

 your journal, but I venture to send you this brief and 

 imperfect account of it. A Cleveland resident, to 

 whom I have read this, is quite confident that it was 

 a smaller insect which was thus disporting itself. 



Edward Abbott. 



Cleveland, O., July 9. 



[The ' Canada soldier ' sent is a large ephemerid, 

 found in immense numbers about the Great Lakes. 

 The pulsating swarms of small insects seen about 

 the tree-top were undoubtedly formed of gnats (Chi- 

 ronomidae), allied to the mosquitoes. The phenome- 

 non has been frequently witnessed, both in this 

 country and in Europe, to the great astonishment of 

 the spectators. — Ed.] 



