Irifnisires of Lake Jfemplirenun/og. — Jfarsfers. 25 
form a continuous ridge in the fossil and occupy about one- 
eighth of an inch each. These show bj'^ their position that 
they are the ossified neural arches and along the hinder part 
of the line a double row can be traced consisting of both neu- 
ral and hiemal arches. The presence of distinctly ossified 
spines is not clear. 
An interesting point in the interpretation of the fossil is 
the presence in the place of the stomach of the remains of the 
food. Behind the pectoral fin are the mandibles of a small 
titanichthyoid fish, with other unrecognizable plates scat- 
tered over the interval. Farther back still is a well marked 
ichthyodorulite fluted from end to end so far as it is visible. 
It lies separate from all the other fragments and must be re- 
garded as belonging to the food and not to the fish in ques- 
tion. The original of neither of these relics has yet been 
discovered elsewhere. 
The pala^oniscids are an essentially Carboniferous and post- 
Carboniferous famil}' of fishes, scarcely any of them having 
yet been found below the latter horizon, Cheirolepis trailU 
from the lower Old Red sandstone of Scotland and C cana- 
densis from the upper Devonian of Scaumenac bay, Canada, 
being almost the only Devonian forms. Moreover, it should 
be here borne in mind that this genus has been by some ich- 
thyologists, as by Pander for example, separated from the 
palaeoniscids and placed in a family by itself-theCheirolepidse. 
It is, therefore, interesting to find so well marked a species 
of the family on an horizon so low and in company with as 
old a type as Coccosteus. The origin of the paheoniscids 
must evidently be sought in strata below the upper Devonian. 
CAMPTONITES AND OTHER INTRUSIVES OF 
LAKE MEMPH REM AGOG.* 
By N'ernon F. Marstkks, Indiana I'liiversity, Bloomington, Ind. 
*I wish U) irrHb'fiilly ackiiowledii-f assis(ancc j^iven by Mr. AV. A. Wil- 
son in providing me with a tracinir tnjin a map of lal<t' Mompiin'ma- 
gog on filo in tho officr of llio Canadian (irological Survey, ami from 
wliich I have prepared the accompanying map (greatly reduced) sliow- 
ing the relative position of the diki'S. 
I desire also to e.\])ress my sincere ajipreciat ion of assistance so cheer- 
fully given by Mr. E. M. Kindle (instructor in Indiana University, 18y;{- 
94) and Mr. E. M. Walker, student, in collecting m.aterial under some- 
what adverse circumstances. 
