54 Evolution and Distribution of Fishes 



As not a few geologists have already suggested, the 

 contents of each of these bone-beds must have represented 

 the sudden death and decomposition of as great an accum- 

 ulation of fishes as Goode has indicated above for destruc- 

 tion of the menhaden by its enemies in a year. But since 

 the rock, in which such enormous numbers are mainly found, 

 is often of a hard fissile metallic character, and probably 

 indicates a sudden volcanic dust deposit formed during 

 active volcanic changes in the earth's crust, these hosts of 

 fishes may not only have been killed and entombed, they, 

 enclosed in the dust stratum may have been upheaved above 

 the water, exposed to sun-heat and sun-drying, as well as 

 to volcanic crustal heat, till abundant oils had exuded. 



Now when one geologically examines the areas over 

 the world that are already known to be rich in petroleum, 

 it appears that the great majority of these are in close con- 

 tact with, or have an indirect connection with, strata that 

 abound in fossil fishes. Thus that hitherto richest and most 

 extensively exploited area that extends from West Virginia 

 through Western Pennsylvania and eastern Ohio north- 

 ward through Ontario and Erie to the Great Slave Lake 

 and Hudson Bay, is the region that has yielded a more 

 abundant and varied fish-fauna enclosed in rocks of the Old 

 Red Sandstone or of the Carboniferous age, than any other 

 part of the world. As described also by J. P. Lesley 

 for the Old Red and the Carboniferous systems of Penn- 

 sylvania (jo:II : 1453; III: 1759 : 2565) the numerous 

 extensive and prolific fish "bone-beds" that are intercalated 

 between other strata, form a remarkable feature of these 

 formations as of others described later in this work. 



Redwood again points out (25:1:164) that the Upper 

 and perhaps the Lower Silurian strata of north eastern 

 North America may yet yield abundant supplies of mineral 

 gas, if not of petroleum. While such might represent 

 decomposition products from decay of primitive Silurian 

 cyclostomatous fishes, it is just possible that the primary 

 source of this might result from superincumbent strata of 

 Old Red or Devonian age. Redwood, Engler, and others 

 have shown that petroleum-yielding strata of every age, 

 from the Silurian up to the Tertiary period, occur over prac- 



