[ells] CAMBRIAN ROCKS OF SOUTHERN NEW BRUNSWICK 117 



this division of the system, and consist of the remains of hexactonellid 

 sponges probably allied to the genus Cyathospongia. The second 

 series of organisms is in the upper limestone division of this series, the 

 fossils here found being of a different nature from the ordinary sponge 

 spicules in having a calcareous coral-like structure, somewhat resem- 

 bling certain forms found in the basal portion of the Cambrian else- 

 where. The structure of this organism has not yet been definitely 

 worked out, but it consists of elongated cylindrical objects with bodies 

 from one to three inches across and several inches in length. This 

 is the object described as Archseozoon Acadicum. 



The third zone is that of the graphite beds or graphitic slates in 

 which occur great numbers of sponge spicules, arranged in parallel 

 sets, one set crossing another at an acute angle. This type of sponge 

 is apparently Monactinellid. As only straight needle-like spicules 

 without rays have been obtained of this sponge it probably was a 

 mass of sarcode or jelly, protected and sustained by the spicules 

 which traversed it. 



In a second paper in the same bulletin, 1890, Dr. Matthew more 

 definitely describes the occurrence of these sponges in the upper 

 Laurentian rocks of this district. Here in beds of quartzite associated 

 with the limestone of Drury Cove several miles north-east of St. John, 

 also regarded as of upper Laurentian age, both solitary spicules and 

 fragments of the net-work of a sponge, apparently of the genus 

 Cyathospongia eozoica occur, resembling fragments of Hexactinellid 

 sponges found in the lower beds of the Etcheminian division of the 

 true Cambrian of that area. These forms were also obtained from 

 smooth graphitized layers in the limestone itself as also in large 

 numbers from the graphitic slates associated with the crystalline 

 limestone near the suspension bridge across the St. John river, at 

 the west end of Douglas avenue. These are referred to Sir William 

 Dawson's provisional genus Halochond rites. The horizon of these 

 beds is stated to be the lower half of the upper division of the upper 

 Laurentian. These forms occur in other localities where the contain- 

 ing rocks are highly graphitized. Above these beds, in the original 

 scheme of classification are placed the Huronian system with an 

 estimated thickness of more than 25,000 feet to the base of the Cam- 

 brian as usually understood. 



In considering the horizon of the slates, quartzite and crystalline 

 limestone about St. John just described, it will be seen that any evi- 

 dence derivable from a comparison of these fossils with the supposed 

 organisms from the Grenville and Hastings series, may be practically 

 disregarded. According to the latest examination of these rocks in 

 Quebec and Ontario, they appear to be referable to the Huronian 



