CONTEMPOEA.RIES AND SUCCESSOES OF EOZOON. 139 



sometimes in a linear manner _, sometimes spirally, like 

 those Globigerinae wliicli constitute the mass of modern 

 deep-sea dredgings and also of the chalk. These 

 bodies occur dispersed in the limestone, arranged in 

 thin layers parallel to the bedding or sometimes in the 

 large chamber- cavities of Eozoon. They are so varia- 

 ble in size and form that it is not unlikely they may 

 be of different origins. The most probable of these 

 may be thus stated. First, they may in some cases 

 be the looser superficial parts of the surface of Eozoon 

 broken up into little groups of cells. Secondly, they 

 may be few-celled germs or buds given ofi" from 

 Eozoon. Thirdly, they may be smaller Foraminifera, 

 structurally allied to Eozoon, but in habit of growth 

 resembhng those little globe-shaped forms which, as 

 already stated, abound in chalk and in the modern 

 ocean. The latter view I should regard as highly 

 probable in the case of many of them ; and I have 

 proposed for them, in consequence, and as a convenient 

 name, ArcJiceosjpherince, or ancient spherical animals. 



Carbonaceous matter is rare in the true Eozoon 

 limestones, and, as already stated, I would refer the 

 Laurentian graphite or plumbago mainly to plants. 

 With regard to the worm-burrows referred to in 1865, 

 there can be no doubt of their nature, but there is 

 some doubt as to whether the beds that contain them 

 are really Lower Laurentian. They may be Upper 

 Laurentian or Huronian. I give here figures of these 

 burrows as published in 1866* (fig. 35). The rocks 

 * Journal of Geological Society. 



