424 
The Hon. Mr. Strangways on the 
edges, and in its outliers, it nearly equals the limestone itself if* 
thickness. 
It is said to contain magnesia as a constant ingredient, and the 
appearance of many of its beds agrees with that of similar limestones 
in Britain. Its Flora differs greatly from that of the other soils, and 
may even serve as a help to the geologist. It is marked, even to the 
beginning of November, by the purple flowers of the Geranium 
cicutarium, by which I have often distinguished it ; the streams are 
accompanied by the beautiful tufts of Anchusa officinalis, Polemc- 
nium cceruleum, Aconitum lycoctonum ; the woods contain fewer 
firs, and in some places many wych elms, as on the Tosna. 
The only outlier of this stratum, with which I am acquainted, 
occurs on the brook Pulcovca, above the village of Pulcova. 
Although its outcrop occupies but a small space, yet it may be 
satisfactorily traced by means of the marked character of the 
bituminous clay which supports it. As certain irregularities of dip, 
for which this spot is remarkable, affect equally both strata, I shall 
leave them to be described together hereafter. 
I must also notice a tract on the upper part of the Ishora, where 
for the space of eight or nine versts at least the limestone fails, and a 
red sand rock, sometimes approaching to the character of red marl, 
fills up the interval.* The last place on ascending the eourse of the 
Ishora where the limestone appears in situ , is in the bed of the 
river, a little below Pilny Milny, whence it is dragged up in con- 
siderable quantities. I cannot decidedly name any spot where it 
may be seen in situ on the other side of this tract of sand, but on the 
* I was not able to decide satisfactorily whether this red rock was a protrusion of the 
intermediate bed, or an outlier of the red ground of the interior of Russia, incumbent on 
the limestone. Its lying at higher level than the limestone at Pilny Milny, favours the 
latter supposition. 
