FOSSIL I'LANTS. 



665 



our possession. 



Several similar are also figured 

 m Lindley and Button's work from the same 

 locality, and are there designated trigonocarpim 

 Hoggerathii. Palm leaves and stems are found 

 in great abundance, and in good preservation, in 

 the upper, secondary, and tertiary beds; and in 

 the island of Shcppey, immense numbers of 

 palm fruits and others of tropical climates are 

 found associated with marine shells and fragments 

 of various woods. Fig. 6 is a cone bearing a 

 close analogy to that of the Scotch fir, only 

 smaller, and found in the oolite. Figs, e e and 

 h h, are also fruits resembling those of the palm 

 tribe. 



CYCKDV.M. There are only two existing genera 

 of this family, cycas and zamia, natives of South 

 America, India, China, and New Holland, where- 

 as five fossil genera have been discovered, con- 

 taining about thirty species. These occur chiefly 

 in the secondary strata of the Has, oolite, and 

 chalk, and occasionally, though more rarely, in 

 the tertiary series. These plants seem to have 

 been the chief materials whence the pai-tial beds 

 of lignite or brown coal have been formed. Of 

 this description is the coal of Cleveland Moor- 

 laud, near Whitby ; of Brora in Sutherlandshire; 

 of Buckeberg, near Minden, in Westphalia. 

 The Bo vey coal and lignite of ffiningen are found 

 in the tertiary strata. The amber which is 

 iound on the eastern shores of England, and on 

 the coasts of Prussia and Sicily, is supposed to 

 be a resinous exudation from the beds of lignite, 

 found in the tertiary strata. Fragments of fossil 

 gum wei'e found near London, in digging the 

 tunnel through the London clay at Highgate. 



The cycadese form a beautiful family of 

 plants, and from their structure, assimilate in 

 many respects with palms, coniferse, and ferns. 

 T'he trunk of the cycadejE has no true bark, 

 but is surrounded by a dense case, composed of 

 persistent scales, which have formed the bases 

 of fallen leaves ; these, together with other 

 abortive scales, constitute a compact covering 

 that supplants the place of bark. The leaves 

 rise around a single cone like the pine apple, and 

 are pinnatifid ; the fossil species appear to agree 

 with the recent in the following particulars of 

 structure: 1. By the internal structure of the 

 trunk, containing a radiating circle or circles of 

 woody fibre, embedded in cellular tissue. 2. By 

 the structure of tlieir outer case, composed of 

 persistent bases of petioles in place of a bark, 

 and by all the minute details in the internal 

 organization of each petiole. 3. By their mode 

 of increase, by buds protruding from germs in 

 the axilliE of the petioles. 



A number of silicified fossil trunks of cyca- 

 dea3 are found in the isle of Portland, immedi- 

 ately above the surface of the Portland stone, and 

 l>elow the Purbeck stone. They are lodged in 

 the same beds of black mould in which tliov 



grew, and are accompanied by prostrate tnmks 

 of large coniferous trees converted into flint, and 

 by stumps of these trees standing erect with 

 their roots still fixed in their native soil."* 



239 



Frond of pteropliylluin. 



This cut represents a portion of a frond, 

 either of a zainia or pterophyllum, found in the 

 lias beds at Cromarty, in the north of Scotland. 

 The structure of the leaflets, which are of the 

 same breadth throughout, would indicate its 

 belonging to the species pterophyllum. (See 

 p. C53). 



Fig. /, cut 2S8, represents a cone of the zamia, 

 as figured by Lindley and Ilutton, from the 

 greensand formations of England. 



In a tertiary fresh water formation at CEnin- 

 gen. Professor Braun has enumerated thirty-six 

 species, chiefly dicotyledons, about two-thirds of 

 which belong to genera which still grow in that 

 neighbourhood, but their species diti'er and cor- 

 respond more nearly with those now existing in 

 North America, tlian with any otlier European 

 species. On the other hand, there are some ge- 

 nera which do not exist in the present flora of 

 Germany, and others not in Europe. Judging 

 from the proportions in which their remains 

 occur, poplars, willows, and maples, were the 

 predominating trees in the former flora of Qinin- 

 gen. Of two very abundant fossil species, one, 

 the populus latior, resembles the modern Cana- 

 dian poplar; the other the populus ovalis, re- 

 i-embles the balsam popular of North America. 

 The determination of the species of fossil willows 

 is more diflicult. One of these, the salix angus- 

 tifolia, may have resembled our present salix 

 viminalis. 



Of the genus acer, one species may be com- 

 pared witli acer campestre, another with acer 

 pseudoplatanus ; but the most frequent species, 

 acer protensum, appears to correspond most 

 nearly with the acer dasyearpon of North Ame- 

 rica. To another species, related to acer negundo, 

 Mr Braun gives the name of acer trifoliatum. A 

 fossil species, liquidambareuropeum, differs from 

 the existing 1. styracifluum of America, in hav- 

 ing the narrower lobes of its leaf terminated by 



* Auckland Gcol. Transact, 



