2 AIR-BREATHERS OF THE COAL PERIOD. 



That there was dry land, even in the Lower Silurian period, we 

 know, and can even trace its former shores. In Canada our old 

 Laurentian coast extends for more than a thousand miles, from 

 Labrador to Lake Superior, marking the southern border of the 

 nucleus of the American continent in the Lower Silurian period. 

 Along a great part of this ancient coast we have the sand-flats of 

 the Potsdam Sandstone, affording very favorable conditions for 

 the imbedding of land animals, did these exist ; still, notwithstand- 

 ing the zealous explorations of the Geological Survey, and of 

 many amateurs, no trace of an air-breather has been found. I 

 have myself followed the Lower Silurian beds up to their ancient 

 limits in some localities, and collected the shells which the waves 

 had dashed on the beach, and have seen under the Silurian 

 beds, the Laurentian rocks pitted and indented with weather 

 marks, showing that this old shore was then gradually subsiding ; 

 yet the record of the rocks was totally silent as to the animals 

 that may have trod the shore, or the trees that may have waved 

 over it. All that can be said is that the sun shone, the rain fell, 

 and the wind blew as it does now, and that the sea abounded in 

 living creatures. The eyes of trilobites, the weathered Lauren- 

 tian rocks, the wind-ripples in the Potsdam sandstone, the rich 

 fossils of the limestones, testify to these things. The existence 

 of such conditions would lead us to hope that land animals may 

 yet be found in these older formations. On the other hand, the 

 gradual failure of one form of life after another, as we descend in 

 the geological series, and the absence of fishes and land plants in 

 the older Silurian rocks, might induce us to believe that we have 

 here reached the beginning of animal life, and have left far behind 

 us those forms that inhabit the land. 



Even in the Carboniferous period, though land plants abound, 

 air-breathers are few, and most of them have only been recently 

 recognized. We know, however, with certainty that the dark 

 and luxuriant forests of the coal period were not destitute of ani- 

 mal life. Reptiles crept under their shade, land-snails and milli- 

 pedes fed on the rank leaves and decaying vegetable matter, and 

 insects flitted through the air of the sunnier spots. Great interest 

 attaches to these creatures ; perhaps the first-born species in some 

 of their respective types, and certainly belonging to one of the 

 oldest land faunas, and presenting prototypes of future forms 

 equally interesting to the geologist and the zoologist. 



It has happened to the writer of these pages to have had some 



