Bibliography. 209 



nutest organic forms, by the statement " that the granular portions of 

 the oolitic limestone of the Jura formation, in Germany as well as in 

 England, appears to be chiefly composed of the shells of Melonise." 



He alluded to the different views which have been entertained with 

 regard to the origin of granular (kornigen) oolitic limestone, and stated 

 that the idea, that like peastone, it originated in an incrustation of va- 

 rious small fragments in a former sea having a high temperature, was 

 improbable and untenable ; for among the round grains with concentric 

 coatings, like the peelings of an onion, which might be supposed to 

 have had such an origin, there also often occurred calcareous or sili- 

 ceous bodies of the same size, which showed no trace of incrustation, 

 as for example spines of Echinse, encrinital plates, fragments of shells, 

 and minute Polythalamia. All these forms which had existed and re- 

 mained in the same conditions, but which had received no shelly cov- 

 ering, prove that the shells of many oolitic grains can be no incrusta- 

 tions. Besides, the oolitic grains have generally a very similar limit 

 with regard to size, while in the formation of peastone there is no limit. 



The author stated that he possessed a piece of oolitic limestone from 

 Baden, the grains of which showed in addition to the shells, longitudi- 

 nal strife, and chambers were visible in the cross section, so that the 

 structure opposed the supposition of a mere calcareous deposition. 

 The same structure was seen in the Melonise from the mountain lime- 

 stone of Lake Onega in Russia, and by means of sections distinct views 

 of the structure of the Melonise were also obtained, in a piece of horn- 

 stone from the mountain limestone of Tula, to which a Spirifer remained 

 adhering, and which was crowded with various Polythalamian forms. 



Ehrenberg states that in many cases " the Melonise of the oolitic 

 limestone are so changed into calc spar that the shells are no longer 

 divided. In other cases there is found in their interior a small kernel 

 of calc spar which might easily lead to the supposition that a real in- 

 crustation of a grain of sea-weed had taken place, while it is in fact 

 only the internal commencement of the change to crystalline calcareous 

 spar, as may be recognized by the brilliant fracture. 



The author states the microscopic organisms from Australia and 

 New Holland present less peculiarity than was expected in consequence 

 of the remarkable forms of the larger animals of those regions. Only 

 one peculiar genus, Rhizonotia, was found, and all the forms belonged 

 to well known orders, classes, and families. 



The following are the general results from all these examinations. 



" 1. Microscopic life, particularly in the forms which constitute 

 masses of earth and rock, appears to exist in the same manner over the 

 surface of the whole earth. 



Vol. XLTii, No. 1.— April-June, 1844. 27 



