136 PICTURESQUE SKETCHES 



the south of Belgium, near Luxemburg. In these 

 cases the first and most important indications of change 

 are seen in the increased proportion of argillaceous 

 matter, accompanied often by carbonate of lime. The 

 character of a calcareous clay, sometimes passing into 

 a muddy limestone, may be traced in most of the 

 varieties of this formation. 



The lias * is everywhere singularly rich in the 

 remains of organic existence ; these remains extend- 

 ing through almost all the tribes of marine animals, 

 and including, though rarely, fragments of wood and 

 other vegetable bodies. No conclusion, indeed, can 

 be drawn as to the nearness or distance of the 

 land whence these fragments floated, for they are 

 often covered with marine animals ; but since, as 

 will be seen, it is not unlikely that many of the 

 monsters of the deep at this time repaired to the 

 shallows, or even to the shore, to deposit their eggs, 

 we may, perhaps, be allowed to conjecture that 

 the land was not far distant from the spots now occu- 

 pied by these strata. 



The muddy liassic beds deposited after the sand- 

 stones described in the previous chapter, although 

 they contained a considerable proportion of carbonate 

 of lime, were not in a condition favourable for the 

 development of coralline existence, and the remains of 

 such animals are accordingly rare. This is not the 

 case, however, with the closely allied group of Zoo- 

 phytes known as the Crinoidea ; for they, on the 

 other hand, were singularly abundant, and were mani- 

 festly an important group, perhaps assisting to clear the 



* So named probably from the appearance of the bed in riband-like 

 layers of different colours observed in some parts of England. 



