GAEL VON LTNNE AS A GEOLOGIST NATHORST. 731 



After having described several " wild mussels " ( Anomise) , Linne 

 remarks : 



The animals which inhabited all these " wild mussels," as well as the un- 

 altered shells, are nowadays unknown to us, as we never find them in any of 

 the collections of mollusks, nor do we know what in the world may have 

 become of them. Still, we shall never believe that a species has entirely 

 perished from the earth. 



That Linne believed that the seas were all too insufficiently explored 

 for anyone to form a decisive opinion as to whether the animals in 

 question really were extinct is shown with desirable clearness from 

 what he says in the same work about the belemnites : 



No matter how common these may be now, their origin, as well as that of 

 the ammonites, " Darts," " Brattenberg's pennies," and Brachiopoda, remains 

 entirely unknown. Perhaps all these animals sustain themselves in the deepest 

 parts of the sea, and never come ashore. It would therefore be desirable if 

 those who go to the Indies would search the Sargasso Sea and find out whether 

 they do live there now. 



At the present time even the layman knows that rock strata contain 

 numbers of extinct animals, but this fact had not been established at 

 the period in question. It may, for example, be remembered how 

 Scheuchzer interpreted the giant fossil salamander from the stone 

 quarries at Oeningen to be the skeleton of a man who had perished 

 in the supposed " deluge." Linne's opinion that distant seas should 

 first be explored before drawing any conclusions as to wdiether the 

 animals in question were extinct or not was evidently the right one. 

 That the conclusions arrived at were sometimes rather hasty (as when 

 groups of animals which have living representatives at the bottom 

 of the sea were supposed to be extinct) is shown among other things 

 by the discovery of Rhizocriniis lofotensis^ a discovery which caused 

 such excitement at the time it was made. 



At Bursviken on Gotland Linne had an opportunity of observing 

 cobbles of the kind of limestone known as " oolite," or " fish roe 

 stone," and on this occasion he expressed himself against the opinion 

 that it might be petrified fish roe. 



The cobbles of the uppermost " auren " are of a species of stone called 

 " Oolithum " by the Lithologi, because it consists of a white hailstonelike rock 

 having one crust outside of the other, just like a crab's eye [eyestone], or sugar 

 pill. Those who have proclaimed that such an Oolithus was nothing else than 

 petrified fish roe would here have an opportunity of seeing more stone i"oe than 

 ever there was true fish roe in the world.<^ 



°' In the Systema Naturte the oolite is mentioned among the limestones (not 

 among the fossils), and of its origin it is said: " Natum e calce coalescente 

 fluctibus maris rotundata," i. e., it is considered as a purely mechanical forma- 

 tion. 



