58 ANNUAL REPORT OF 



Another very notable difference is that the Boonton fishes do 

 not have round or cyloidal, over-lapping scales ; but instead, these 

 are rhomboidal, enamel-like and typically united by a peg-and- 

 socket articulation. And again, we must take due note of the 

 fact that the tails of the Boonton fish are very unlike those of 

 modern Teleosts, or "bony fishes," the vertebral column project- 

 ing into the upper caudal lobe and making that lobe longer and 

 larger than the lower lobe. The unsymmetrical or heterocercal 

 caudal fin, and the presence of fine ray-lets or "fulcra" along 

 the borders of all the fins are characters by which the fossil species 

 may be told at a glance, from the vast majority of recent forms. 



Reconstruction of Physical Conditions. — An investigation into 

 the nature of sedimentation over the Triassic area enables us to 

 reconstruct more or less perfectly in imagination the former 

 environment of the Boonton fish fauna, and to account with some 

 plausibility for the sudden extinction and preservation of vast 

 numbers of creatures. 



Both in New Jersey and New England the inference may be 

 drawn from a variety of evidence, such as geographical surround- 

 ings, composition of the sediments, presence of ripple-marks, 

 abundance of land plants and similar indications, that the rocks 

 of the Newark group were laid down under shallow-water con- 

 ditions in proximity to the land. In the Connecticut Valley 

 region the strata were clearly deposited in a sort of embayment, 

 bounded on either side by eruptives of the mainland, and it is 

 even possible to determine the current directions over part of this 

 area, as has been done by Professor Emerson, of Amherst. As 

 the tide rose and fell, alternately covering and leaving bare exten- 

 sive mud-flats, huge reptiles, the like of which no longer exist, 

 roamed in large numbers up and down the shore, searching their 

 prey and leaving tell-tale footprints, which have been preserved 

 from their day to this. 



Little else but footprints bears witness to 1 the existence of these 

 weird creatures, a fact which offers a striking commentary on the 

 imperfection of the palseontological record. Although for a long 

 time regarded as imprints made by birds, it is now known that 

 these are traces of reptiles belonging to the order of Dinosaurs, 

 whose gait was bipedal. In New Jersey, also, similar tracks have 



