GEOLOGICAL HISTORY OF NEW YORK. 645 



that a depressed area once existed between the New York ridge and 

 the New Jersey highlands, and that this trough was an estuary swept 

 by the tides, much like the Bay of Fundy. Here, as there, the shallows 

 and mud-flats exposed by the ebb were places of resort for many of the 

 animals inhabiting the district ; but there is this difference, that in the 

 lapse of time the fauna of the country has completely changed, and 

 the fishes which inhabited the waters of the Triassic estuary, as well 

 as the reptilian monsters that perambulated its shores, have now ut- 

 terly disappeared from the face of the earth. 



The fishes of the Trias, being found at various localities both in 

 New Jersey and the Connecticut Valley, early attracted attention, and 

 many of them were described by Mr. W. C. Red field for many years 

 a leading scientist of New York. More recently large collections of 

 them have been made by the writer, so that now they are pretty well 

 known. They form some twenty species of four genera all ganoids 

 related to the Lepidosteus and Amia of our interior lakes and rivers. 



Of the molluscous life of the age in this region we, know almost 

 nothing, since the marine deposits which contain its remains are not 

 now above the ocean-level, and the fresh-water and estuary beds ex- 

 posed to our observation have yet yielded none. Of the land-animals 

 scarcely any traces have been found except their footprints. These 

 prove that a motley crowd of reptiles and amphibians, some of huge 

 size, and, according to our notions, of uncouth and hideous shapes, 

 thronged the shores of our Triassic bay in such numbers, so swift and 

 so well armed for attack and defense, that this must have been anything 

 but a congenial place of residence for a peaceably-disposed citizen. 



The hills which overlooked the Triassic lagoons as they now do 

 their exposed beds, the plains of New Jersey were covered with for- 

 ests of Araucarian pines, and the lowlands with thickets of sago- 

 palms and ferns, while gigantic scouring rushes lined the marshy shores. 

 There were no oaks, maples, nor walnuts in the forests, and proba- 

 bly no flower-bearing shrubs or herbs in the undergrowth, for nearly 

 all the fruits and flowers belong to the angiosperms and palms, nei- 

 ther of which had yet made their appearance on the earth's surface. 

 Hence, the vegetation must have been sombre and uninteresting, com- 

 pared with that of the present day, and, as there were no grasses in 

 it, ill-adapted to the wants of man or the higher animals. 



At the close of the Triassic age this region became the scene of 

 great and destructive physical changes, which must have completely 

 altered its aspect. Along the Triassic belt, both east and west, sub- 

 sidences took place, or displacements by lateral pressure which tilted 

 up all the strata until they stood at an angle with the horizon of 15, 

 where they still remain those on the east dipping eastward, those of 

 New Jersey toward the west. At the same time deep fractures reached 

 the source of molten matter below, and this was forced up, either in 

 dikes through vertical fissures, or in sheets between the beds of the 



