ORCiANISMS IN ACADIA. • 141 



all angles. This bed marks the close of the peculiar physical conditions which caused the 

 fauna below to dilfcr from that found in the Paradoxides beds. Possibly one of these 

 conditions was a difierence in the temperature of the sea-water in which these animals 

 lived. Rapid accumulation of sediments, instal)ility of the sea-bottom, and possibly 

 volcanic eruptions at no very distant point, added their influence in giving the lower 

 beds a distinct fauna. In and below this bed, the remains of trilobites are rare, and, 

 except as regards the brachiopods, the known launa differs entirely from that in the 

 beds above. In the middle " assise" (16') we have been able to recognize an Agraulos, 

 and at the base (16') an Ellipsocephalus, both recalling forms which in Europe are 

 associated with Mesonacis Kjeriilfi. 



In the Cambrian basin on Long Reach, King's county, a line Obolus was collected 

 on Caton's Island near the base of Baud b, which helps to link this fauna with that of the 

 fucoidal sandstone in Sweden. In its peculiar ornamentation, and in the way in which 

 its radular sculpture is confined to the half of the shell nearest the umbo, it closely 

 resembles the Lhigula (?) or Obolus (?) favosa, of that arenaceous deposit. 



In the same basin, but at a locality further west, Band b in its upper part contains 

 the curious little cephalopod, Volborthella, heretofore known only from the Blue Clay of 

 Russia. It occurs there in the upper part of the Blue Clay in association with Mesonacis, 

 Mickwitzia, Platysolenites, etc. 



The relation of the Paradoxides beds to those beneath will be better understood by a 

 comparison of the Acadian measures at the several localities with the typical Cambrian 

 series of Sweden. So nearly alike were the physical conditions during the early period 

 of Cambrian time in those two countries that the symbols, originally used in New 

 Brunswick to designate the groups of beds in the Paradoxides division, have served to 

 distinguish nearly similar subdivisions in Sweden and Norway. 



In the Acadian sections the base of the Paradoxides beds has been taken as the 

 datum line, and the thickness of the beds above and below this horizon indicated on a 

 scale of 100 feet to an inch. 



In Sweden the beds which belong to the lower part of the column, and are marked 

 b, are the " Oleuellus beds" of that country; those marked a are the Fucoidal and 

 Eophyton sandstones which by the discoveries of F. Schmidt in Western Russia are also 

 to be eoimted as a part of the " Olenellus " beds, since, as already observed, the corres- 

 ponding beds in Russia contain a Mesonacis. The brachiopod Lingula (or Mickwitzia) 

 monilifera, which is found with this trilobite, and is common to the Cambrian of Russia 

 and Sweden, occurs in the latter country at the base of the Eophyton sandstone, and this 

 sandstone appears to correspond in position to the white-weathering sandstone a at the 

 base of the St. John group or to the upper part of the Basal series immediately below. 



Of the sections of Cambrian rocks in Acadia exhibited in the above table, three are 

 from the St. John basin, and the fourth from the Long Reach basin in King's county, and 

 they show clearly the varying thickness of the deposits of Division 1 in the different 

 districts. This feature is much more noticeable in the lower Bands (a and b) than in the 

 upper (c and d). 



The most continuous and complete section found is that on Hanford Brook, which 

 drains a small Cambrian basin now separated from the rest of the St. John basin by a low 

 ridge of pre-Cambrian rocks ; and from the differences that are observable in the details 



