Geology of the Environs of Petersburg. 429 
immediately under the soil, to some distance beyond Peterhof, where 
they cover the sandstone of the intermediate bed. The outcrop or 
termination of which towards Strelna is so covered up by them, 
that I am not satisfied as to the exact point where it should be laid 
down ; although, as the same diluvium covers the veined clay again 
on the Ivanovca, and occurs on the Ligovca, we may place it 
perhaps in the neighbourhood of Strelna without much error. The 
increase in elevation of the bank about that place would favour this 
supposition. 
The hills of Khamouzy, Coirova, Penty, and the ridges which 
connect them with that of Pulcova, shew only diluvian gravel down 
to their foundation, although their elevation is very considerable.* 
It is possible that the hill of Pulcova contains the extremities of the 
Pulcova outlier, but nothing is apparent except diluvian gravel. 
The deep gullies and cliffs of the streams of Great and Little 
Coirova, which unite and form the Goirovca on issuing from the 
hills, are hollowed out in diluvium to two-thirds of their depth, 
and barely one-third at the bottom is scooped out in the blue clay. 
This gravel in like manner reaches up to the foot of the ridge of 
Shulcova and Doudorof (Plate 80), and is spread over all the rising 
ground of Carlina behind Tzarscoe Celo ; it thus so completely 
obscures the junctions of the limestone and subjacent rocks, and the 
shape of the ground is so calculated to deceive by presenting escarp- 
ments where there are no outcrops, and no escarpments where it 
conceals a considerable outlier, that I cannot give the outlines of the 
* The height of the hill of Khamouzy would lead to a suspicion that there existed in 
it an outlier of the limestone, or at least of the intermediate bed, which is seen at the 
mouth of the denudations of Tarelova and Remeleva, in the escarpment opposite. The 
hill being thickly wooded and presenting no sections, I must leave it for the present as a 
point meriting further investigation. 
