182 SKETCHES OF CREATION. 



names and virtues are commemorated on the brown stone 

 slabs still standing in the oldest cemeteries. The sheets 

 of this formation were spread out in an elongated depres- 

 sion in the surface of the older and underlying formations. 

 On each side of this belt of horizontal sandstones we reach 

 a limiting wall of tilted gneisses and bubbling granites. 

 These were the land while the waters of Long Island Sound 

 stretched through an estuary up to New Hampshire, and 

 received there the waters of the embryo Connecticut. If 

 the student of the world's history will go to the Portland 

 quarries, he will see, spread over the ground in the vicinity 

 of some of the offices, slabs large and small, bearing traces 

 like the imprints of the feet of birds. These track-bearing 

 layers of the rock are found at all depths in the quarry. 

 The formation is generally believed to belong to the later 

 Triassic or earliest Jurassic (Fig. 73). 



The ornithic character of the footprints has been stren- 

 uously argued by Dr. Deane, the discoverer, and Professor 

 Hitchcock, the first describer of these ichnolites. This 

 opinion has been supported by the weight of such names 

 as Buckland, Lyell, Mantell, and Forbes ; but all observa- 

 tions hitherto made on the distribution of organic types 

 through geological time tend toward the general principle 

 that every class-type of vertebrates, and every ordinal type 

 of invertebrates, has been introduced upon the earth in the 

 line of succession indicated by its rank, and there is an d 

 priori improbability of the existence of so high a type of 

 organization as we find in birds — and birds of the size that 

 these must have been — at a time when the reptilian type 

 had scarcely reached its culmination. 



Moreover, the Pterodactyls have made us acquainted 

 with the existence and characters of bipedal reptiles in 

 the very age when the bipedal footprints of the Connecti- 

 cut sandstone were impressed. It should be noted, also, 



