THE STATE GEOLOGIST. 57 



of Protospondyli. The next most important genus, Catopterus, 

 and the nearly related Dictyopyge, have a less highly modified 

 organization, and thus approach more closely to the primitive 

 sturgeons, or Palcconiscidcz. Acentrophorus, though not occur- 

 ring in the New Jersey Trias, is present in the Connecticut Valley 

 region, and belongs with Semionotus amongst the Protospondyli. 

 Hence, the afore-named genera, under which the majority of local 

 species are comprised, may all be regarded as more or less prim- 

 itive sturgeon-like fishes. Of the remaining genera, each of which 

 is represented by a single species only, Diplurus is a member of 

 the fringe-finned and Ptycholepis of the stout-finned or division 

 of Ganoids. The Newark series is totally lacking in remains 

 of sharks or lung-fishes, a circumstance which may possibly 

 be associated with sedimentary conditions. These latter will be 

 considered immediately. 



For the benefit of many who may not be specially familiar with 

 the teachings of palaeontology, or who have but slight acquaint- 

 ance with fossil fishes in general, it may be well to point out very 

 distinctly that the Boonton fishes differ markedly from ordinary 

 types of fishes now living. Consequently, the statement which 

 one hears frequently asserted with more or less positiveness that 

 this or that fossil specimen is exactly like a modern perch, or 

 sun-fish, or other familiar form, springs from ignorance and 

 careless observation. The nearest comparison with modern types 

 that can be made is, as we have already explained, with the stur- 

 geon, a comparatively rare form, and notably distinct from our 

 common fresh-water fishes. One of the most obvious character- 

 istics of the latter, as everyone knows, is that they have bones. 

 The very name of "shad" is immediately suggestive of a fish "full 

 of bones." That is to say, there is, first of all, a "back-bone," 

 or ossified vertebral column, with stout spines above and below; 

 secondly, there are well-ossified ribs, these being a conspicuous 

 feature, and lastly, in many forms at least, there are numerous 

 fine inter-muscular bones. The head also, in modern bony fishes, 

 is well ossified. But none of the Boonton fossils exhibit these 

 features, save only in some species the ribs and vertebral arches 

 (but not the centra or body of the vertebrae) are imperfectly 

 ossified. 



