THE EARLIER FORMS OF LIFE. 



269 



ical analysis, so that whatever cannot be determined in the one will be 

 ascertained by the other method. 



He was accordingly gratified to recognize in one of his rock-sec- 

 tions the fragment of a rhizopod. The structure has some resem- 

 blance to the acaleph Chcetetes, but on account of the minuteness of 

 the layers it should be classed with the rhizopods, reminding one very 

 much of the Stromatopora. Figs. 7 and 8 illustrate these organisms 

 magnified thirty-five diameters, thus making the breadth of the cells 

 only y^o f an i ncn - The smaller figure is probably a section of the 



Fig. 8. Protozoan Fossil, from Hanover, N. EL 



same rhizopod, cut in a different direction. The rock holding these 

 fossiliferous bits is diabase, a variety common between Connecticut 

 Lake and Bellows Falls, both in New Hampshire and Vermont. 



Since the naming of Stromatopora by Goldfuss fifty years since, 

 naturalists have separated the acaleph structures from the true corals, 

 but this genus is generally regarded as different from either of them. 

 Prof. Hall described it as a polyp-coral in his "Paleontology of New 

 York," but would not so regard it now. The most common form of 

 it, as figured by him, is herewith presented (Fig. 9), from the Niagara 

 limestone of Lockport, occurring in masses one or two feet in diam- 

 eter. It is a protozoan coral, assisting in the work of reef-building, 

 however, as much as the polyp-structures. By way of comparison 

 we add a figure of a bryozoan mollusk (Lichenalia concentrica), 

 from the same formation and locality with the Stromatopora (Fig. 

 10). The relations of our new specimens are rather with the first of 

 these forms, and will probably be described hereafter as species of 

 Stromatopora. 



It is an interesting fact that these " layer corals " have impressed 

 the minds of all students of the Eozoon by their resemblances to the 



