A careful analysis of this fauna of the Cliffwood clays brings clearly to view several important facts. In the first place, the large number of species which are common to the fauna, and to one or more of the faunas of the formations above, emphasizes the close relationship between the Cliffwood fauna and these higher faunas. This relationship is, indeed, so close that they constitute essentially but different faunules of one large fauna. There is no sharper distinction between the fauna of the Cliffwood clays and the Merchantville clay than there is between the Merchantville and the Woodbury clays. However, the Cliffwood fauna does possess characteristics which distinguish it somewhat sharply from the Merchantville fauna, among which may be mentioned the abundance of the species Pteria petrosa and Isocardia cliffwoodensis, which have nowhere yet been recognized in the Merchantville, and the especial abundance, in some cases at least, of Veleda lintea, which is sometimes present, although always rare in the Merchantville. None of the crustaceans which are so abundant in the Cliffwood fauna have been recognized in the Merchantville, although claws and other disarticulated joints of crustacean appendages are not uncommon in the higher fauna at some localities. The distinction between these two faunas is not alone emphasized by the species present in the Cliffwood and absent from the Merchantville, but also by the genera and species which are absent from the Cliffwood and almost universally present in the Merchantville fauna. Among such genera may be mentioned Idonearca, Trigonia, Panopea, Axinea, and Leiopistha.

On making a careful comparison between the Cliffwood fauna and that of the Woodbury clay, the formation immediately above the Merchantville, a much greater resemblance is noted than between the Cliffwood and the Merchantville; the same Merchantville general mentioned above as being conspicuously absent from the Cliffwood fauna are also conspicuous for their absence from the Woodbury. Furthermore, several forms are common to the Cliffwood and the Woodbury faunas which have not been observed in the intervening formation, among which may be mentioned Breviarca, Lucina cretacea, and the little crustacean here called Tetracarcinus subquadratus. In making this comparison, however, it must not be overlooked that some of the most characteristic Cliffwood species, as Isocardia

cliffwoodensis and Pteria petrosa, have nowhere been observed in the Woodbury fauna.

It is unnecessary to make comparison between the Cliffwood and the Marshalltown faunas, as there is scarcely anything in common between them; but with the fauna of the Wenonah sand the Cliffwood fauna has more in common even than with that of the Woodbury clay. Among the species listed in the table given above, it will be seen that fourteen species are recorded as being common to the Cliffwood and the Wenonah, eleven to the Cliffwood and the Woodbury, and only ten to the Cliffwood and the Merchantville. These numbers do not fully express the relative proximity of relationship between these several faunas, although they do partially, because no account is taken of the relative abundance of the forms noted. As a matter of fact, when the abundance of the different species in the different faunas is taken into account, the similarity of the Cliffwood and Wenonah faunas is accentuated, while that between the Cliffwood and the Merchantville is diminished. Aside from the crustaceans of the Cliffwood fauna, the two species Pteria petrosa and Isocardia cliffwoodensis are perhaps the most characteristic forms, and both of these occur in the Wenonah fauna. Veleda lintea is another conspicuous Cliffwood species which occurs more frequently in the Wenonah sand than in any other of the New Jersey Cretaceous formations.

It is believed that these comparisons which have been instituted make clear the fact that, however much or however little the Cliffwood fauna has in common with the faunas of the higher formations, it does have a unity of its own. Although many of the species occur also in other horizons, the whole assemblage of species, considered as a faunule, possesses characteristics which serve to distinguish it from any of the other faunules with which it has been compared.

The geographic distribution of this Cliffwood fauna differs notably from that of the Merchantville, it being limited, so far as now known, to a small area between Cliffwood Point and the head of Cheesquake Creek. The distribution of the Merchantville fauna is entirely across the state, from the south shore of Raritan Bay to the shores of Delaware Bay; throughout its entire extent it is remarkably constant in its characters, and the Merchantville beds are everywhere marked

by constant lithologic characters, yielding fossils, usually in abundance, wherever they are well exposed. There is scarcely a formation in the entire Cretaceous series of New Jersey which is more sharply marked, both lithologically and faunally, than the Merchantville clay. The base of the formation constitutes an easily recognizable and perfectly natural geologic horizon, the beds below being characterized by the great heterogeneity of their lithologic characters, while the beds above are just as strongly characterized by the constancy of their lithologic characters.

The heterogeneous assemblage of sands and clays beneath the Merchantville have been called the Raritan formation, and the fossi'iferous clays at Cliffwood which are interbedded with sands and are lithologically allied to the subjacent beds, must certainly be considered as a lens-like body included in the Raritan. The Raritan beds for the most part give evidence of a non-marine origin, but there must have been marine conditions present along the Atlantic border at no great distance during the entire period of their deposition. The non-marine, perhaps estuarian conditions of Raritan time were supplanted in Merchantville time by more uniform marine conditions, but, previous to the initiation of marine conditions in the area entirely across New Jersey, we find evidence here in the Cliffwood clays of a slight transgression of the sea from the direction where marine conditions had continuously existed, and the occupation of a small area where non-marine sediments had previously been deposited.

This occurrence at Cliffwood of marine fossils in the Raritan is not the only case of the kind in New Jersey, although it is the most notable one. Whitfield' mentions the occurrence of Turritella encrinoides, a not uncommon species in the Cliffwood beds as well as in some of the higher formations, in the clays at Sayersville, which are near the very base of the Raritan; and the slab mentioned by him, bearing many examples of this species, is now preserved in the collections of the Geological Survey of New Jersey. Other specimens of marine fossils from near the same locality have recently been acquired by Mr. J. M. Manley, of New Brunswick, N. J. It is altogether possible, and indeed most probable, that faunas more or less closely allied to those of the higher formations were living, throughout the

1 Paleontology of New Jersey, Vol. II, p. 144.

entire period of deposition of the Raritan beds, at no great distance from the present shores of Raritan Bay; and, if that were the case, it is not at all surprising that there should be occasional transgressions of marine conditions within the area where non-marine sedimentation was usually in progress, with the consequent deposition of marine beds with marine fossils.

THE HALLOPUS, BAPTANODON, AND ATLANTOSAURUS

BEDS OF MARSH

S. W. WILLISTON

The University of Chicago

HALLOPUS BEDS

In the American Journal of Science for October, 1891, Professor O. C. Marsh proposed the name "Hallopus beds" for a somewhat indeterminate horizon of vertebrate fossils, as follows:

Near the base of the Jurassic a new horizon may now be defined as the Hallopus beds, as here alone remains of the remarkable reptile named by the author Hallopus victor have been found. Another diminutive dinosaur, Nanosaurus, occurs in the same strata. The horizon is believed to be lower than the Baptanodon beds, though the two have not been found together. The Hallopus beds now known are in Colorado, below the Atlantosaurus beds, but quite distinct from them.

The Baptanodon beds have been found in many localities everywhere beneath the Atlantosaurus beds, and having below them, at various localities, a series of red beds, which may, perhaps, contain the Hallopus horizon, but are generally regarded as Triassic.

This reference of Marsh to a vertebrate horizon below the marine Jurassic of the Rocky Mountain region has been wholly overlooked or disregarded by subsequent writers, the fauna itself having been referred to the "Upper Jura." I am now in a position, I believe, to show that the horizon is a distinct one, and that it belongs, not to the Lower Jurassic, but to the Upper Triassic. I, furthermore, believe that the horizon will eventually be found to be widely fossiliferous in the Rocky Mountain region.

Although I cannot be entirely sure, after so long an interval, it is my recollection that the type specimen of Hallopus victor was discovered by Mr. M. P. Felch in August, 1877, in Garden Park, near Cañon City, Colo., a few weeks before the time of my first visit to that since famous locality. The precise spot whence the specimen came was pointed out to me, the base of an escarpment of red sandstone, whither the specimen had fallen from the overhanging.