6 Notice of the Wonders of Geology. 



The fossiliferous formations have assumed a high degree of 

 interest in our times, an interest which is constantly increasing 

 with the progress of geology. In the earlier periods of the science, 

 the primary rocks were the chief objects of investigation, and 

 fossil geology, being little cultivated, was little understood. The 

 primary rocks were viewed as the types of permanency, the pri- 

 mordial foundations laid down in the beginning, and which, as 

 was supposed, had rarely been disturbed in the progress of ge- 

 ological events. But now we cannot assign a period beyond 

 which there has not been change, event, and revolution. Granite 

 itself, in the early systems of geology the very personification of 

 physical antiquity and stability, is now proved to be of all geo- 

 logical ages, anterior to the tertiary; and it would in no manner 

 surprise us, were the progress of discovery to place granite in 

 some of its irruptions, above the tertiary, like the ancient lavas 

 of Auvergne, many of which repose upon the tertiary of that re- 

 markable country. 



The light which has burst in upon us from the microscopic dis- 

 coveries of Ehrenberg, has opened a new world in the mineral 

 kingdom; for none would have expected to find minerals and 

 rocks composed of the silicified, ferruginous, and calcareous pet- 

 rifactions of infinitesimal animalcules, requiring thousands of mil- 

 lions of individuals, to fill the capacity of a cubic inch. 



In all probability, we are to proceed in these discoveries from 

 flint, opal, chalcedony, agate, tripoli, and beds of sand, and clay, 

 and marl, to earlier formations, which also may contain their myri- 

 ads of invisible animalcules. Dr. Mantell has presented this sub- 

 ject with his usual felicity, and with good figures of many mag- 

 nified fossil animalcules ; while his remarks evince an expectation 

 that even the most ancient rocks may not be exempt from simi- 

 lar evanescent fossils. It is, however, not easy to understand 

 how any organic body can retain its form in the midst of fusion, 

 and although silicified shields of animalcules may be proof, to a 

 certain extent, against fire, we cannot suppose that they can re- 

 main, with their characteristic forms, in the midst of granite and 

 porphyry, while the very quartz and feldspar, of which they are 

 so largely composed, have flowed in igneous fusion, or acquired a 

 condition by fire so soft and yielding as to admit of crystalliza- 

 tion. The absence, therefore, of traces of animalcules from ig- 

 nigenous rocks, would not necessarily prove that their materials 



