232 The American Geologist. October, 1893 
surface. The gradation from the rocks of this old moraine 
to those of the diagonal moraine was observable but did not 
cover over ten feet of length of flow. At the lower end of the 
diagonal moraine there was no gradation and no dump, nor 
were there any traces indicating that its lower end had been 
trailed along the slope of the lateral moraine. After some 
search I fail to find that such a formation has been observed 
before. 
Note. — I would suggest that the "diagonal moraine" described by 
Col. Plummer may be of the nature of an osar. The rounded and as- 
sorted material of which it is composed appears to have been deposited 
in a tunnel by an englacial stream and afterward brought to the sur- 
face by the melting of the ice. — I. C. Russell. 
REMARKS ON SPECIFIC CHARACTERS IN 
ORTHOCERAS. 
By Aug. F. Foerste, Dayton, Ohio. 
Species of Orthoceras, when examined closely are found to 
be subject to considerable variation. Within the limits of 
the same species, the apical angle, the hight of the chambers, 
the concavity of the septa, and the curvature of the sides of 
the individual annulations forming the siphuncle, may vary. 
In fact in any large suite of specimens it would not be diffi- 
cult to find variations in these characters within the same 
specimen. The detection of such variations is often the re- 
sult of extremely careful measurements, but in other cases, 
both of species and individuals, variation may often be rec- 
ognized even on hasty examination. In proportion as the 
student is supplied with a larger collection the differentiation 
of the species naturally becomes more difficult. The exami- 
nation of the exterior markings of the shell then becomes a 
means of considerable assistance; to such an extent, in fact, 
that the genus has been divided by Hyatt into a series of sub- 
genera, based chiefly upon distinctions of the various types 
of surface ornamentation. These are mainly of two kinds, 
annular and longitudinal. Annular ornamentations evidently 
originated in variations in growth of the thickness of the 
shell, and annularly striated species of Orthoceras may be 
