24 FOREST LANDS OF NORTHERN RUSSIA. 
and in France. There are the ferns with a foliage often 
meagre and leathery, equisetacese of the genera equisetum 
and phyllotheca, cycads, conifers, and lastly some rare 
monocotyledons. There are there also the forms which 
are the most generally diffused in England and France, in 
the Bathonian, the Oxfordian, and the Coralline, and 
which is seen at Scarborough in Yorkshire, at Mamers in 
France, and at St. Michael, near Verdun. The resem- 
blance to these found at Scarborough and with those 
found at St, Michael is very striking. 
‘The flora of Cape Boheman contains thirty-two species; 
a third, about ten of them, havé been found, moreover, 
and always in the inferior oolite, or the brown jura of the 
Germans. Amongst the ferns, the Scleropteris pomelit 
Sap., a species of St. Michael, is especially characteristic, as 
it denotes the presence of a genus which is essentially 
oolitic. The genus Phyllotheca, a type of equisetacer 
which has been for a long time extinct, has been found, 
first in Australia, and thereafter, by Professor Zigno, in 
the Oxford strata of the Venetian Alps. It was then 
there, a genus of which the extension was immense. And 
the Polar species Phyllotheca lateralis, described by Phillips 
and Lindley under the name of Eguisitum laterale, has 
just been found in Siberia. We have here, then, a most 
curious type, the sheaths of which, split in segments, 
distinguishes it from the true Zquisitum, and approximates 
to the schizoneuva of the Trias, which is found towards 
the centre of the jura spread over the whole land, though 
everywhere pretty rare. 
‘This was doubtless a type ina state of rapid decadence, 
but one which, from that circumstance, seems well fitted 
to throw light on the equality of temperature which was 
still general at that moment from one end of the globe to 
the other. The cycads alone number eight species out of 
the thirty-two, more than a fourth part of the whole; and 
in regard to frequency of occurrence they hold the first 
rank, The genus Podoszamites predominated amongst 
them: this genus distantly recalls the Zamia of the 
