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By J. C. MANSEL-PLEYLELL, F.G.S., F.L.S., 

 &c., &G., President. 



HE Geologist has but few opportunities of 

 acquainting himself with the Flora of any 

 past period, because the perishable parts of 

 their structures, unless rapidly covered over, leave 

 scarcely any traces. The actual vegetation therefore 

 of a formation is rarely met with, and still more so 

 the old land-surface on which it grew. Exceptions are 

 the coal-fields of the Carboniferous age, and the Dirt- 

 Beds of the lower Purbecks, from which the fossil I 

 now propose to bring under your notice was exhumed. 

 It belongs to an order of plants which, although 

 exogenous has some links of affinity with Cryptogams. 

 This Gymnospermous order includes Conifera^, Cycadeee, 

 and GnetaccEe, the earhest flowering plants known ; of 

 these three, the Coniferai only now grow in Europe. 

 They are distinguished from the higher forms of Cryp- 

 togams, mosses, equisetse, and ferns (which also have 

 leaf-appendages and vascular tissue), by bearing a 

 distinct flower, a seed which is naked, and the stems 

 having rings of annular growth. In point of time the 



