342 NATURAL SCIENCE. 



JULY, 



Walcott (ii, p. 1 66) assented to Ford's argument, remarking that 

 Olenelliis " expresses, in one of its species at least, the decadence " of 

 the Paradoxides type. But he frankly admitted that Olenellus gilberti 

 showed a permanent retention and great development of what were 

 regarded as embryonic characters, and he accordingly recognised 

 in this species a " retrogression." In the same paper an admirable 

 amount of work is published on the Olenellus-fauna, regarded as 

 Middle Cambrian ; and a new genus, Mesonacis (ii, p. 158), is put 

 forward for Olenellus vermontana (Fig. 2), which now rejoices in its 

 full 26 thoracic segments and a broad, not styliform, pygidium. 



Into this scene of zoological and geological contentment Dr. 

 Brogger suddenly discharged a bomb-shell. In a remarkable paper 

 (12) on the Olenellus-zone in N. America, he pointed out that in 

 Europe Olenellus preceded Paradoxides, and urged that, from a 

 comparison of the faunas, made possible by the extensive work of 

 Walcott, there was "no reasonable doubt" that the Olenellus-zone 

 in America was also on the lowest level. Walcott, finding the New 

 York area still difficult of interpretation, at once pushed his researches 

 to Newfoundland, and gave us the complete section, in unbroken and 

 undisturbed strata (14), at Manuel's Brook, Conception Bay. The 

 American sequence straightened itself out ; the Lower Cambrian of 

 the Hudson River was shown to have been thrust by a profound 

 fault over on to the Ordovician rocks (ig, p. 526); and we have 

 now the beds of Georgia, Vermont, with Olenellus, as Lower 

 Cambrian ; the St. John and Avalon beds, with Paradoxides, as 

 Middle Cambrian ; and the Potsdam and Belle Isle beds, with 

 Dikellocephahis and Olenus, as Upper Cambrian. The basement-bed 

 at Manuel's Brook is a coarse conglomerate, and rests directly upon 

 " Algonkian " gneiss. Thanks to the intercommunication made 

 possible by scientific journals, the work of Brogger and Holm in 

 Scandinavia, and of Schmidt in Russia, thus rapidly bore fruit in 

 North America ; and Olenellus assumed its place as marking the 

 earliest known fauna of the globe. The next fauna that may be 

 found below it — and hints of this are already darkly scattered (22) — 

 will be of true Precambrian age. 



The triumph was to William Smith, a man grossly ignorant of 

 phylogeny ; ' it only remained to re-explain the relationship of 

 Olenellus and Paradoxides (16, p. 39). The child had proved to be 

 the father ; and the arguments in the contrary direction have been 

 readjusted to everyone's satisfaction. It is a case of 



" By the Lord, I knew ye, as well as he that made ye." 

 After this, we can only admire the courage of Messrs. Peach and 

 Home (24, p. 240) in suggesting that Olenellus is the central point 

 in which the more modern trilobites, the Limuloids, and the 

 Merostomata, converge. 



^ See his " Stratigraphical System of Organised Fossils," 1817, p. vii. 



