16 A POPULAR SKETCH OF THE GEOLOGY 



and Mollusca, since we find corals, encrinites and shells in great abun- 

 dance at Ticknal and the other before-mentioned places. This sea, 

 after being partially filled up by these materials, which were deposited 

 by a slow and gradual process, became subject afterwards to new 

 conditions, the animals which inhabited it gradually perished, and its 

 place was either occupied by freshwater, or it itself was filled with 

 materials swept from freshwater and from the land. These materials, 

 strewed in repeated successions over wide areas, consisted either of 

 mud, sand, or vast accumulations of vegetable remains. The mud 

 when deposited at the bottom and partially indurated, became shale, 

 or when containing much iron was converted into ironstone, the sand 

 was compacted into sandstone, and the vegetable substances undergo- 

 ing a chemical change beneath the vast pressure of the superincum- 

 bent materials, were turned into beds of coal. These vegetables when 

 examined by the botanist, are immediately declared by him to have 

 been the produce of a tropical temperature, and the greater part to 

 have lived upon the land, although all differ and many of them widely 

 so, from any now known to exist. The perfect state of their parts 

 forbids the supposition that they were washed from any distant re- 

 gions, and though we cannot point out where the land was situated 

 on which they grew, we are yet assured that this portion of the globe 

 was once much hotter than at present, and that its lands were co- 

 vered with the thick and matted vegetation of an Indian forest. The 

 period which the coal measures occupied in their formation was long 

 enough to allow of many successive growths and partial destructions 

 of whole forests, and for different materials to be successively and 

 gradually accumulated, till they formed a thickness of considerably 

 more than a thousand feet. 



At the close of this period, and before any of those materials 

 which now rest upon the coal measures were deposited, great distur- 

 bances took place over this district. Dislocating and upheaving 

 forces acting from below, broke up the coal measures and other pre- 

 viously existing rocks, caused the great faults which are everywhere 

 found in them, set on edge the masses of mountain limestone north- 

 east of Ashby, and bent up the Cambrian rocks which now form the 

 hills of Charnwood Forest. It may be asked, how it is known that 

 all these dislocations took place at this precise period, after the for- 

 mation of the last of the coal measures, namely, and before the depo- 

 sition of the upper part of the new red sandstone. The latter condi- 

 tion is quickly verified from the facts before mentioned, that the 

 beds of new red sandstone when lying on the upturned edges of the 



