6 L. W. BAILEY : 



cation relating thert'to by the late Prof. Hartt,' the total number of organic forms recog- 

 nized was limited to eight genera (four genera, including thirteen species, of Trilobitcs, 

 and six species of Brachiopods) there are now recognized from the same formation four 

 species of Protozoa (sponges), two of Hydrozoa, one Cystid, twelve Brachiopods, seven 

 Pteropods, two G-asteropods, six Phyllopods, four Ostracoids, and at least thirty-two 

 species of Trilobites ; among the latter one, the Paradoxides regina, being the largest fairly 

 complete example of the genus yet found in any part of the world. 



But it is not solely, nor even chiefly, in the recognition of new species that these 

 researches are important. It is largely in the information which they afford as to the 

 relationships of specific types and the phases of their developmental history that they 

 acquire greatest interest and value. They are still further of importance as helping to 

 establish more exactly the range and relations of the entire Cambrian fauna, both as 

 regards its own subdiAÙsions and those of subsequent periods. As originally described 

 under the name of the St. John Group, the formation was regarded as including only 

 the series of dark slates and sandstones, at the base of which were found the Paradoxi- 

 des and other forms by which Prof Hartt was enabled, in 1868, to fix their age as Primor- 

 dial, and the probable eqvxivalent of Barrande's Stage C, as represented in Bohemia. At 

 the same time a series of red beds, of considerable thickness, was found to intervene 

 between these fossiliferous strata and those of the older volcanic or Huronian Group, and 

 though at first referred to the latter as an upper member, was subsequently regarded as 

 being more intimately associated with the former. At a still later period, the uncon- 

 formability of the Primordial series, as including these red beds, to the underlying 

 Huronian, was placed beyond question by inA^estigations extending along their entire 

 lines of contact ; but it is only quite recently that evidence has been found, by Mr. 

 Matthew,' tending to show that between the Paradoxides beds and the supi^osed equiva- 

 lents of the Huronian, two physical breaks, rather than one, intervene, the red rocks 

 being really unconformable to tlie overlying as well as the underlying series. A dis- 

 covery of still greater interest, made at the same time, was that of the occurrence in these 

 same beds, of organic remains which, though few and somewhat obscure, seem sufficient 

 to show the existence, in this part of America, of a fauna older than that of the Paradox- 

 ides zone, and the equiA'alent of the Lower Cambrian fauna of Newfoundland, or that of 

 the Caerfai G-roup of Wales. Thus, the whole Cambrian system at St. John, originally 

 described collectively as Primordial, has now been shown to be divisible into two dis- 

 tinct series, of which the first, Series A-B, the Basal or Georgian Groui), includes the 

 Olenellus fauna, while the second. Series C, the St. John Group or Cambrian proper, 

 includes part of the Lower and the whole of the Middle Cambrian as recognized in 

 Europe, being equivalent to the Solva and Menevian groups of Hicks, and the Lingula 

 flags of Murchison, as well as the Kegiones B and C of Augelin. Series D, the equiva- 

 lent of the Potsdam Sandstone, so far as known, is absent from Acadia. Of the groups 

 represented, the St. John Group is further regarded as embracing three stages or divi- 

 sions, including in the first division four subgroups or bands, each characterized by its 

 own peculiar forms of organic life. Thus, so far as the Maritime Provinces (and New- 



' Geology of Southern New Brunswick, Frederioton, 18G5. 



^ On a Basal Series of Cambrian Rock.s in Acadia, Can. Record of Science, vol. iii, no. 1, 1888. 



