54 PETRIFACTIONS AND THEIR TEACHINGS. CHAP I. 



traces of terrestrial vegetation to the present time. 1 The 

 trunks and branches, leaves, and the fruits or cones, of nume- 

 rous trees of this family abound in a fossil state, and in the 

 Case before us, there are many interesting specimens which 

 our limits will not permit us to dwell upon. There are fruits 

 of pines and firs from the Crag deposits, and from the green- 

 sand of Kent ; and foliage and stems of pines, araucarise, 

 thuytes, c., from the Lias and Oolite. 



'Voltzia. The Case ^also contains some fine specimens of 

 Voltzia, a genus peculiar to the Triassic deposits, and one of 

 the most characteristic of the extinct fossil coniferse. The 

 leaves of these plants are alternate, and have much analogy 

 in their form and arrangement with the foliage of the Arau- 

 carise. The fruits are oblong cones, with scales slightly im- 

 bricated, which do not appear to have been contiguous, are 

 cuneiform, and generally have from three to five obtuse 

 lobes : the disposition of the seeds or grains is not determined. 2 



Fossil Cycadeom Plants. The Zamise and Cycadese are 

 plants with cylindrical stems, beset with thick scales, which 

 are the bases of petioles that have been shed : the summit of 

 the stem is crowned with elegant pinnated leaves with simple 

 veins, and which in the young state are coiled up like a crosier, 

 as in the ferns. The Zamiae are generally short and robust 

 plants, but the Cycadese are longer, and some species are bifur- 

 cated, and attain a height of from twenty to thirty feet. The 

 fruits bear a general resemblance to the cones of the pines, 

 but the seeds are naked. The Cycadeae are natives of hot and 

 humid climates, and inhabit the West Indies, Cape of Good 

 Hope, the Molucca Islands, Australia, &c. 



Numerous extinct species and genera of this family occur 

 in a fossil state, and they are especially abundant in the 

 secondary deposits the Lias and Oolite. In England the 

 most fruitful locality is the Yorkshire coast, near Scarborough, 

 where, in the intercalated fluvio-marine clays and shales of 

 the Oolite, leaves and fruits of numerous species are found in 

 great variety and perfection. The foliage is changed into 



' The association of coniferae with palms and arborescent ferns in 



the tertia^ eaSUreS ' C0ntinues throu S h a11 th e subsequent formations to 



2 Two species of Voltzia are figured in " Wonders of Geology," p. 547. 



