Black Earth of Central Russia. 71. 
a parallel trough ranges to the southward, from Hawkesbury in 
Cape Breton Island to Windsor, on the south side of the Basin of 
Mines (lat. 44° 49', long. 64° 19' west); and three miles further 
south he also discovered coal-measures, rising with a northwardly 
dip of 45° from below the gypsiferous rocks, and resting on granite. 
Coal is likewise reported to occur at Beaver Lake, south-east of 
the Albion mines, and to be brought down the East River during 
the spring floods, attached to floating ice. On the north side of 
the valley of the Stewiack, south-west of the Albion mines, coal- 
measures rest on a deep bed of limestone which dips to the south. 
The gypsiferous strata, and the associated shales, sandstones, and 
fossiliferous limestones, Mr. Logan is of opinion, are not only newer 
than the coal-measures, but overlie them unconformably, founding 
his conclusions respecting the geological age of the formation on its 
organic contents. ‘The fossils, he states, have been determined to be 
distinct from those of the carboniferous or any lower epoch, as well 
as from those of the lias or any superior deposit, but to have a de- 
cided generic agreement with the fossils of the triassic period. 
At Horton Bluff, ten miles north of Windsor, and not far from 
gypsum beds, but between which and the point in question is a 
fault, some dark-coloured argillaceous strata alternating with cal- 
careous bands are well exposed. Carbonized vegetable remains are 
not uncommon in these beds, which might easily be mistaken for 
coal-measures; but as one of the calcareous bands is nearly identical 
in character with the Windsor limestone, and as he also obtained a 
slab which appears to him to exhibit foot-marks, the author is in- 
clined to consider the deposit as affording collateral evidence of the 
age of the gypsiferous strata. 
A paper wasafterwards read “ On the Tchornoi Zem, or Black Earth 
of Central Russia,” by R. I. Murchison, Esq., Pres. G.S. In this 
communication the author describes, first. the range and extent of 
the Black Earth; secondly, its chemical composition ; and thirdly, 
he offers some remarks respecting its origin. 
1. The northern boundary of the Tchornoi Zem may be defined 
by a line drawn in a curved direction from a little south of Lichwin 
(lat. 54° N., long. 33° 44’ E.) eastward to the Volga, in the 57th 
degree north latitude, occupying the left bank of that river west 
of Tcheboksar, between Nijni Novogorod and Kasan. It occurs 
also plentifully on the Kama and around Ufa; and on the Asiatic 
side of the Ural mountain it occupies an extensive district near 
Kamensk, in Jat. 56°, and another between Miask and Sviask. Its 
northern and southern limits in Siberia were not ascertained, but it 
was found in the Baschir country on both flanks of the southern 
Ural, and in the steppes of the Kirghis, Between Orenburg and 
the mouth of the Volga it is wanting, the surface of the district 
consisting of marine detritus, containing shells of species which 
now exist in the Caspian: it appears to be equally wanting south 
of T'zaritzin on the Volga (iat. 48° 40’), as well as in the steppes of 
the Kalmucks, occurring in only very limited patches along the Sea 
of Azof, or south of the granitic steppes. It abounds, however, to 
