Clifton College Scientific Society. 95 



Of course the question will arise — how is it that all these 

 live creatures were submerged and fossilised, and how is it 

 that some were preserved in such a wonderful way ? I 

 think the best reason to give is, that they were suddenly 

 engulfed while alive, and covered over with mud, which came 

 down the rivers into the sea after a flood, as is frequently the 

 case nowadays. With regard to many specimens of the 

 Enaliosaurs, in which the head and neck and tail bones are 

 in the natural position, while those of the body are in con- 

 fusion, a very probable reason is, that the dead body floated 

 on the water until the gases had distended it and it had 

 become coiTupted. The solid parts then falling together 

 were still kept in a sort of bag by the tough outer skin, until 

 it became waterlogged and sank. 



Another characteristic feature of the Whitby formation is 

 the jet. This is, in structure, closely allied to coal, and its 

 presence can be accounted for by the vegetable remains found 

 in the Lias. 



The trees, especially conifers, are abundant. These coni- 

 fers are referred to five genera, and they resemble more 

 closely the Araucarian division than any European pines. 

 Many, if not all of them, seem to differ from living forms in 

 having large piths. There are other kinds of vegetable 

 remains, such as the Sigillarise and the Stigmarise, the 

 exact nature of which has not yet been determined. The 

 flora of the Liassic age (as of the carboniferous period which 

 it succeeded) was extremely different from that now exist- 

 ing. We are struck, at the first glance, by the similarity of 

 the ferns to those now living, and the dissimilarity of almost 

 all the other fossils except the coniferre. Among the ferns 

 it is not always easy to decide whether they should be placed 

 in existing genera or not ; but, in regard to most of the other 

 contemporary forms of vegetation, it is difiicult to guess 

 their family, or even their class. 



The ferns of both the Carboniferoiis and Liassic periods 

 are generally found without the organs of fructification, 

 though in a few specimens they have been well jjreserved. 

 Since, however, their rarity prevents these organs being 

 used as a basis of classification, the genera have been divided 

 by the branching of the fronds and the arrangement of the 

 veins. 



The larger portion are supposed to have been the size of 

 ordinary European ferns, but many show a decidedly arbores- 

 cent appearance. 



