65 
Class, CEPHALOPODA 
Order, Ammonoidea 
Family, cardioceratidae 
The family name was published first by Hyatt who included Cardio- 
eeras, CadoceraSf Quenstedioceras (Hyatt^ always spelled it this way so we 
can not accept Quenstedioceras as Buckman insists nor Quenstedticeras as 
Reeside demands), and N eumayria. H. Douville’s supposed publication 
was not distributed. In 1900 Hvatt attempted to change the name to 
Cadoceratidae, but this is not valia. Also some later writers have included 
a lot of utterly unrelated genera, which has caused some confusion. How- 
ever, excellent summaries of the family have been given by Buckman^ 
whose interpretation of the group is clear and connected. Many genera 
occur in North America as yet unreported. For instance, among the species 
described by Reeside® under “Quenstedticeras^^ and Cardioceras there are 
a dozen or so generic groups; some named, some unnamed. Two known 
genera and one new genus occur in the Upper Jurassic deposits of the 
Harrison Lake country. The occurrence of species of Cadoceras in the 
Mysterious Creek formation establishes the general age of that deposit. 
Also it establishes the exact date of Paracadoceras gen. nov. which is asso- 
ciated with Cadoceras. Also it establishes the approximate date of Lillo- 
ettia and Buckmaniceras, family Macrocephalitidae, which occur a short 
distance above Cadoceras and associated with cadoceratoid forms close to 
Cadoceras, but not sufficiently fully grown to be generically identified. 
Genus, Paracadoceras nov. 
A cadoceratoid serpenticone. The young is like that of Cadoceras, 
but inflation that supersedes the elevation of the whorl is so moderate that 
the mature form is only a robust serpenticone. Ribbing notably prorsira- 
diate. However, the genus differs strongly from Prorsiceras Buckman in 
that the number of secondary ribs is less than double that of the primaries, 
and in its narrow umbilicus and depressed whorls. Also in the ventral 
ribbing. 
Paracadoceras harveyi sp. nov. 
Plate XVI, figures 1, 2; Figure 2 
Ornament. In the young that part of the rib within the umbilicus is 
reclined as in the Canadian and Alaskan Cadocerata, but at 27 mm. dia- 
meter this part of the rib becomes versiradiate. The extrumbilicate portion 
of the rib is prorsiradiate at all stages. Ribs cross venter with only a 
slight forward bend. Venter is almost smooth on last part of last whorl. 
Table showing number of ribs in a quadrant at various stages. 
Diameter 
18 mm 10 primaries 14 secondaries 
34 “ 8^ “ 14 
53 “ 8 “ 15 
JHyatt: Bull. Geol. Soc, Am., vol. 3, p. 410 (1892). 
*Type Ammonites, vois. II and III (1913-1921). 
*Reeflide: U.S. Geol. Suxv., Prof. Paper 118 (1919). 
