436 
The Hon. Mr. H. Strangways on the 
Near the village of Lukozy is a vast accumulation of fragments 
of the limestone of different varieties. 
The limestone boulders are never found north of the outcrop of 
that stratum whence they are derived, and rarely on the table-land 
itself. Such as are found there are chiefly fragments of the harder 
varieties, which occur in situ , in the hills of Doudorof. They are 
more numerous about Gatchina, and encrease in number along the 
Ishora, and in general towards the south. On the surface of the 
limestone plateau, particularly south and west of the upper lake of 
Doudorof, are several long low ridges, which appear to be entirely 
composed of heaps of rolled pebbles of various descriptions. They 
are on a large scale, exactly like what are deposited by counter 
currents and eddies in running water. 
At the quarries near Mishkina, belonging to Count Camerofsky, 
on the escarpment between the Ishora and Tosna, I have seen 
the surface of the limestone, when scraped bare of superficial 
accumulations which are ten feet thick, presenting hollows and 
steps from one bed to another, the edges of which are all rounded 
as if waterworn. The diluvium in this instance is entirely free 
from stones. 
From the situation of the parent rocks of such of the primitive 
boulders as yet have been identified, and from the increase in quantity 
of the secondary pebbles on approaching the south, it seems that 
the great debacle, or stream of transportation, came from the north ; 
while, from the great height at which the rolled blocks are found, 
it is evident, not only that portions of rocks, whence they have been 
brought, once existed at a higher level, but also that they were 
deposited in their present situation before the excavation of the 
Gulf of Finland and the vale of the Neva. These great denudations, 
together with those smaller ones which open into them, were not 
