1889.] Geology and Palceontology . 625 
two, all of which appear to extend to the flattened or very slightly 
elevated centre. Rays and costae continuous, passing down the outside 
of the cell wall and over the intercellular spaces. Rays and costae 
down to the base of the cell walls alternating in size. The entire 
under surface of the corallum, except the point of attachment, covered 
by a strong, wrinkled, epithecal crust. This is a finely marked species, 
and differs in many important respects from its associate, P. woodniani. 
This species occurs in the Rockford shales, at both Rockford and 
Hackberry, Iowa. — Clement L. Webster, Charles City, Iowa. 
On a Species of Plioplarchus from Oregon.— The genus 
Plioplarchus Cope was established ^ to receive two species of percid 
fishes, discovered by Dr. C. A. White in a stratum overlying the 
Laramie formation in Dakota. The writer has called attention to the 
existence of fishes in the shales near Van Horn's ranch, on the John 
Day River, Oregon,^ and has suggested that these shales belong to the 
Amyzon beds. According to Condon, their position is below the 
John Day Miocene. Dr. Charles Bendire, U.S.A., obtained, among 
the collections from that region with which he has enriched science, 
some specimens of these fishes in a condition sufficiently good for 
identification. They include four individuals which belong to a single 
species of the genus Plioplarchus. They elucidate the characters of 
the genus as follows : 
The vomer, premaxillary, and dentary bones carry teeth of small 
size in moderate numbers. An elevated supraoccipital crest. The 
lateral line is present, and the scales are feebly cetenoid. The ventral 
fins are sustained by a spine in front ; the number of the rays cannot 
be made out. The character of the borders of the operculum and 
preoperculum cannot be determined, but no serrate edges are presented 
in any of the specimens. Tail furcate. 
The specific characters are as follows: the mouth is small, and 
opens obliquely upwards. Premaxillary and dentary teeth in several • 
rows. Size larger than that of the P. whitei Cope, and the scales are 
less numerous, and of larger size. The spinous rays are less numerous 
than in that species and the P. sexspinosus. Formula ; D. xi.-? ; A. 
vii-? 12; the soft anal rays at least twelve, possibly more. Scales in 
five or six rows above the vertebral column, and in ten or twelve below 
it. Radiating ridges of proximal portion, strong ; disc and distal 
portion scarcely roughened. Caudal vertebrae, 15. 
1 Amer. Journal Set. Arts, 1882 ; Tertiary Vertebrata, Cope (Vol. III. Report U. S. 
^ Proceeds. Amer. Philos. See. 1880, p. 62. 
