274 PALAEONTOLOGY ! FOSSIL ORGANIC REMAINS. 



are still distinctly recognisable under the microscope, and 

 large masses of white and yellow resin are sometimes found 

 between the concentric ligneous rings. Among the vege- 

 table substances inclosed in amber there are male and fe- 

 male blossoms of native needle-leaved trees and cupuliferae ; 

 but distinctly recognisable fragments of Thuia, Cupressus, 

 Ephedera, and Castania vesca, intermingled with those of 

 Junipers and Firs, indicate a vegetation different from that 

 now subsisting on the coasts and plains of the Baltic." 



We have now passed through the whole series of forma- 

 tions in the geological portion of the general view of nature, 

 from the eruptive rocks and most ancient sedimentary 

 strata, to the alluvial soils on which are scattered the frag^ 

 ments of rock known by the name of " erratic blocks/' The 

 dissemination of these blocks has been the subject of much 

 discussion; it has been attributed to glaciers, and to floating 

 masses of ice ; but I am inclined to ascribe it rather to the 

 impetuous flow of waters from reservoirs in which they had 

 long been detained, and from which they were set free by 

 the elevation of mountain chains. ( 333 ) It is a point which 

 will probably long continue undecided, and to which I only 

 incidentally allude. The most ancient members of the 

 transition series with which we are acquainted are the 

 schists and greywacke, containing remains of marine plants 

 of the sjlurian, or, as it was before called, the cambrian sea. 

 On what do these oldest formations rest, or, supposing the 

 gneiss and mica schist beneath them to be merely meta- 

 morphosed sedimentary rocks, on what were the oldest sedi- 

 mentary strata deposited ? May we venture a conjecture on 

 that which cannot be the subject of actual geological obser- 

 vation ? According to an Indian mythus, the earth is sup* 



