212 FOREST LANDS OF NORTHERN RUSSIA. 
nated among vegetables, but only within the perimetre ot 
a littoral zone of rather limited extent.’ 
The productus and spirifer spoken of are bivalves like 
the cockle and mussel, the shells of which are found 
with many others in the mountain limestone, and in it 
alone. What is so called is, as has been stated, a series of 
limestone strata lying immediately below the coal measures, 
and, in some cases, alternating with them. They extend 
over great part of Central and Northern Europe; they 
are found again in the lake district of America, and they 
extend to the borders at least of the Arctic Ocean, extend- 
ing between the parallels of 6U° and 70°, stretching 
towards the mouth of the Mackenzie River. The nature of 
the organic remains found in them, as well as the con- 
tinuity of the calcareous beds of homogeneous mineral 
composition and the great thickness of the deposits, concur 
to prove that the whole series was formed in a deep and 
extensive ocean, in the midst of which, however, there 
were many islands. Amongst other characteristic fossils 
are the encrinites, popularly known in some localities as 
St. Cuthbert’s beads and ammonites, and the bivalves 
mentioned, 
After tracing the relations of numerous allied plants, 
and the characteristics of those found in different localties, 
and the successive changes observable in strata of succes- 
sive formation, he states that the primeval type, or pale- 
zoic stock, of the Salisburias and their allies appears to be 
the Psygmophyllum of Schemper, and that in all the cir- 
cumstances of the case it might have been expected that 
some remains of plants possessing the same characteristics 
would be found in Bear Island. Such he considered 
remains figured by M. Heer under the name of Cardiop- 
teris polymorpha et frondosa.* 
Count Saporta then gives some details in regard to the 
* Kohlen fl. d. Biéren. Insel. ; tab. xiv., fig. 1-4. 
