224 PICTURESQUE SKETCHES 



ing in all essential points the same, the picture thus 

 given may be looked on as neither false nor exag- 

 gerated, however imperfect, and as, to a certain 

 extent, characterising the whole of the long period 

 during which the oolites were being deposited. From 

 time to time, in various places during this period, 

 coral reefs were formed, mud-banks accumulated, 

 and occasionally a considerable quantity of sand was 

 also brought in ; and thus there went on a series of 

 changes, resulting in the formation of many important 

 beds of limestone and much clay, along a coast-line 

 gradually advancing eastwards, and probably under- 

 going numerous alterations of level. 



At length this terminated, and a large tract of land 

 was brought very near the present coast of Ger- 

 many; while, in central Europe, the sea was deep- 

 ening, and scarcely even a chain of islands indicated 

 the great mountain ranges of the Alps, the Pyrenees, 

 the Carpathians, or the Caucasus. At this time it is 

 most probable that no great east and west subterranean 

 movement had acted on the part of the earth's crust 

 now above water in the northern hemisphere, and 

 possibly the first intimation of such a disturbing force 

 may be traced, though faintly, in the existence of 

 a considerable estuary, in which our Wealden beds 

 were deposited. From the condition of the upper 

 Portland beds, we find, that, just at the close of the 

 oolitic period, there were very numerous changes of 

 level induced over a small area in the south-east of 

 England, then most likely not far from the coast-line 

 of a large continent. 



Although, however, we have good proof of the 

 existence of a considerable tract of land, the number 



