78 THE DAWN OF LIFE. 



lias not been moulded on the forms of the serpentine and 

 augite, but these have filled spaces or chambers in a hard cal- 

 careous mass. This conclusion is further confirmed by the 

 fact, to be referred to in the sequel, that the serpentine in- 

 cludes multitudes of minute foreign bodies, while the cal- 

 careous matter is uniform and homogeneous. It is also to be 

 observed that small veins of carbonate of lime occasionally 

 traverse the specimens, and in their entire absence of struc- 

 tures Other than crystalline, present a striking contrast to the 

 supposed fossils. 



" 2. Though the calcareous laminse have in places a crystal- 

 line cleavage, their forms and structures have no relation to 

 this. Their cells and canals are rounded, and have smooth 

 walls, which are occasionally lined with films apparently of 

 carbonaceous matter. Above all, the minute tubuli are 

 diS'erent from anything likely to occur in merely crystalline 

 calc-spar. While in such rocks little importance might be 

 attached to external forms simulating the appearances of 

 corals, sponges. Or other organisms, these delicate internal 

 structures have a much higher claim to attention. Nor is 

 there any improbability in the preservation of such minute 

 parts in rocks so highly crystalline, since it is a circumstance 

 of frequent occurrence in the microscopic examination of 

 fossils that the finest structures are visible in specimens in 

 which the general form and the arrangement of parts have 

 been obliterated. It is also to be observed that the structure 

 of the calcareous laminae is the same, whether the intervening 

 spaces are filled with serpentine or with pyroxene. 



" 3. The structures above described are not merely definite 

 and uniform, but they are of a kind proper to animal organ- 

 isms, and more especially to one particular type of animal 

 life, as likely as any other to occur under such circumstances : 

 I refer to that of the Ehizopods of the order Foraminifera. 

 The most important point of difierence is in the great size and 

 compact habit of growth of the specimens in question ; but 

 there seems no good reason to maintain that Foraminifera 

 must necessarily be of small size, more especially since forms 

 of considerable magnitude referred to this type are known in 



