NORTH AMERICA AND THEIR VERTEBRATE FAUNA. I03 



FOOD-SUPPLY. 



The food-supply of the actively carnivorous forms is easily recognized. 

 The large coprolites belonging to the Pelycosaiirs and larger amphibians con- 

 tain abundant reminders of the fate of numerous fishes and smaller reptiles 

 and amphibians. The frequency with which armored forms occur is ample 

 evidence of a persistent and effective campaign for subsistence maintained by 

 the larger carnivorous forms. Unfortunately we are unable to distinguish 

 between the coprolites of different genera or species. No single specimen has 

 been determined as belonging with any particular animal, and so no direct 

 evidence of the food has been found. 



If we turn from direct evidence to indirect and examine the possible 

 sources of supply, we find that little of the vegetation preserved offers much 

 in the way of food for the doubtfully herbivorous forms. Ferns, horsetail 

 rushes, lycopods, cordaites, cycadofilices, sphenophyllales, and conifers — no 

 one of these could have been very readily masticated by animals with such 

 teeth as we know. True rodent, or triturating, teeth would have been neces- 

 sary for such plants as the rushes, or for tearing through the tough outer 

 bark of the lycopods. 



The abundant ferns might have furnished a food-supply if they were 

 eaten. I find but few records of any living forms which eat fern fronds. The 

 partridge is said to do so, and domestic animals will eat the dried fronds when 

 they are taken with the hay, but not in any quantity, and not by choice. 

 They are not touched by grazing animals. Hugh Miller, in his "Testimony 

 of the Rocks," says that existing plants similar to the fossil flora (ferns and 

 their allies) "contribute but little, if at all, to the support of animal Hfe." 

 "The ferns and their allies remain untouched by grazing animals." The roots 

 are edible, and are rooted out by pigs and eaten. Certain North American 

 Indian tribes dug out fern roots and baked them for food. While we can not 

 argue with any certainty that the reptiles of the Paleozoic or Mesozoic did 

 not eat such things, it is very probable that the fronds were as resinous or 

 spicy then as now, and no more acceptable. Diadcdcs and Casea were sup- 

 plied with strong claws, and the former was certainly a powerful excavator. 

 It is possible that the roots of ferns may have formed some, even a consider- 

 able, part of the food-supply. 



Very likely there were a considerable number of soft, succulent water- 

 plants which have left no trace in the coprolites and no records of their exist- 

 ence in the rocks. Moreover, it is to be remembered that the remains of the 

 animals in all probability do not occur in their normal habitat. The bones 

 of such as are found in sandstones and shales or in the soft clays were 

 undoubtedly swept to that place by streams from another locality where 

 plants were possibly more abundant. In certain places, as the patches of 

 light blue clay where the remains of small amphibians, sharks, etc., are gen- 

 erally abundant, plant remains are also common (see White's localities, 

 below), indicating that the animals were entombed in or near their natural 



