io6 Evolution and Distribution of Fishes 



agree closely with the top beds of the Upper Ludlow and 

 with the Temeside groups of England. In 1884 Claypole 

 described the primitive fish Palaeaspis from Silurian rocks 

 of Pennsylvania {62: 1224) and a few years later Mat- 

 thew (<5j:49) described another primitive type — Diplaspis 

 acadica — from Lower New Brunswick in Canada. He 

 correlates the rocks as Niagaran, but they may correspond 

 more nearly with the upper Salina and Waterlime beds of 

 the United States. Associated with the fish — much as in 

 the European beds — Ceratiocaris piisUhis "occurs in myriads 

 in the black fissile shales" (p. 55), and also a crustacean 

 Biinodella hori'ida. Matthew emphasizes three distinct 

 and rather widely separate localities for these Silurian 

 rocks, all of which are devoid of marine organisms, but show 

 freshwater types similar to those of W. Russia, S. Norway 

 (Kiaer), and Scotland. These are the island of Anticosti 

 in the Gaspe or eastern Quebec area of Canada; Arisaig 

 in eastern Nova Scotia; and along Passamaquoddy Bay in 

 southern New Brunswick. Of these he says: "Thus in 

 three districts of Acadia, the lower measures of the Silu- 

 rian series are represented by bituminous shales and lime- 

 stones to the north, and dark carbonaceous shales to the 

 south, which presumably are contemporaneous." And in 

 accepting that these belong to the Clinton groups he adds 

 that the fish remains "occur in the mass of strata included 

 in the 670 feet mentioned in the section at p. 165 of the 

 Report of the Geological Survey of Canada for 1870-71." 



In "The Ancestry of the Upper Devonian Placoderms 

 of Ohio" Claypole {64 : 349) traces the relation of fish life 

 downward from the Devonian to the Silurian beds, and 

 speaking of the Salina beds says: "In these were found 

 the shields of Palaeaspis in great numbers. They are con- 

 sequently of equal age, to say the least, with the Pteraspis 

 of the Ludlow, all of the yet known specimens of which 

 except one solitary shield of Cyathaspis {Scaphaspis) 

 ludensis have come from the upper division." 



But a marked feature of the American area is the ex- 

 tensive deposits or infiltrations of salt that have given the 

 name Salina to the group. Such deposits, however, are 

 restricted to certain beds, and suggest that wide but still 



