23 
‘border of the central bed lies in the southern part of the government of Smolensk, 
near the railroad from Orel to Riga. From this point the phosphatic beds extend almost 
without interruption through the governments of Orel, Koursk, Charkoif, and Voroneje, 
their principal outcrop being not less than 600 kilometers in length, with a breadth of 
from 100 to 200. South of this zone the bed dips to a depth too great to permit its 
being worked, but it re-appears on the southern boundary of the cretaceous basin, as 
is shown by the explorations, still incomplete, which have been pushed in that direc- 
tion. To the north of Voroneje it disappears entirely, giving place to the lower beds of 
the formation, but is seen again between Tambof and Spask for more than 200 kilo- 
meters, and on the east, on the right bank of the Volga, inthe governments of Saratoff 
and Simbirsk. The country between has not been thoroughly explored, but there is 
reason to believe that phosphates crop out in several places. - Their presence should 
also be expected south of Voroneje, beneatl the white chalk that forms the shores of 
the Don. Other beds more or less abundant, but little known as yet, are found in 
Moscow and Nijni Novgorod; also in West Russia near Grodnow. é 
The scientific researches of Professor Schwakhoefer, of Vienna, have established the 
existence of phosphate of lime in the silurian schists of Podolia, along the Dniester, 
where it assumes the shape of great balls; and finally, in the Devonian formation of 
Novgorod, has been discovered a rock containing not less than 12 per cent. of phos- 
phoric acid. Every day new beds are reported, and all the searches hitherto under- 
taken have been crowned with success; and doubtless many deposits remain unknown 
that will be found sooner or later. The condition of the phosphate varies much, as 
well as the thickness of the beds and their depth beneath the surface, but the chemical 
composition is pretty uniform. It usually presents itself under the form of nodules 
similar to those found in the Ardennes, of different sizes, black; brown, gray, green, &c. 
Sometimes, as in the neighborhood of Koursk, Varoneje, and Tambof, it assumes the 
form of schists, and is seen in massive blocks that look like cut stone, which are, how- 
ever, only an agglomeration of large nodules united by a sort of cement; and it is 
chiefly this form in which the stone is employed for building and paving, the scattered 
bowlders, which are usually less hard, not having at present any value for such pur 
poses. The number of layers in a bed varies from one to three, in some cases as many 
as seven, but only one or two are of importance, the rest being merely seams. The 
thickness of the main layers varies from one-fourth to one-half meter, the nodules 
being mixed with gray or yellow sand. Sometimes it is on the surface of the fields, 
and sometimes several hundred feet below. It is everywhere remarked that on the 
outside of the region of phosphates the beds crop out, but in the middle they lie deep. 
Our knowledge of its chemical composition is tolerably precise, thanks to the large 
number of analyses which have been made of it, the results of which exhibit remark- 
able uniformity, and establish the mean of phosphoric acid at about 20 per cent., vary- 
ing from 12 to 33; while the proportion of lime rises from 18 to 50, and carbonic acid 
from 2 to 6 per cent., together with an irregular mixture of sand, clay, and organic 
matter not affected by the acids. The following table will give some idea of the dif- 
ferent samples, and illustrate their richness: 
No. I is the debris of a block of the phosphate from the environs of Koursk, (analysis 
by Professor Claus. ) 
No. II, nodules from Spask, (by the writer.) 
No. III, the same, (by the writer.) 
- No. IV, debris of a block from one of the richest beds of the government of Tambof, 
(by the author.) 
No. V, fossil-bone from the same bed, analyzed by the students of the agricultural 
institute at St. Petersburg. 
No. VI, fossil-wood found in the neighborhood of Spask, in the beds of phosphate, 
(analysis by Professor Engelhardt.) 
No. VII. nodules and organic debris from the beds of the government of Orel, (analysis 
by students of the institute.) 
No. VIII, for comparison, analysis of a nodule from the Ardennes, near Déherain. 
| 
| | 
Bomd dat clay .....<e ee 50.00| 9.50! 59.70} 35.50| 1.45/ 0 7.10 | 33. 40 
Phosphoric acid...... 2202250252... 5% | 13.60 | 27.48} 12.63] 20.26] 31.76 | 35.23 | 29.84 | 20.80 
Perirhenia! acid: -- 5. jo eees. es ss3: 1243.45 3.95 at (Rea SO De et 3. 44 6.06, 2a 
Sulphuric acid........- ab fs See | 0.86 1. 08 0. 44 Quebuloes sues atensse BAG cen = - 
MG Ree tens caw dnote eee eee 21.00 | 42.00) 1854] 29.07] 48.53] 51.90 | 47.99 | 22.50 
MIO 0: EARS Semmes Seton cece en WecOh Gar] Oop re ee Fitts, ilps tel Se 0.47 | 3.00 
Oxide of alumina and iron ........... Wir 272p SeMOW EL 2 3. 47 0. 32 1315 0.89 | 3.80 
It is estimated that the beds of the central zone—that is to say, near Smolensk, Orel, 
Koursk, and Varoneje, contain not less than 44,000 tons to the hectare, while those of 
the government of Tambof, which I consider the richest, will furnish from 50,000 to 
