Tntrusii'es of Lake 3femj)hrema(joy. — Marsters. 35 
power as well as minute and ragged flecks of a brown pleo- 
chroic mineral resembling hornblende. The former may be 
apatite. Irregular bunches of magnetite are exceedingly 
abundant. 
No. 19 is nearly identical with No. 14, with the exception 
that the augite phenocrysts generally show a smaller extinct- 
ion angle. The great portion of the interior is grass green to 
yellowish green with yellow to pink rims. Small inclusions 
of hornblende were observed in the augite. 
No. 24. In this section the colored silicates show the same 
relationships as in No. 19. The plagioclase however is 
unique. It is more abundant than in any section yet de- 
scribed and contains the usual inclusions. The individual 
crystals are arranged with the long axes in the same general 
direction. The fractured and bent shape suggests that such 
an adjustment of the individuals may have been caused by 
great pressure while the magma, although somewhat plastic, 
was sufficiently firm to suffer fracture. This section is an in- 
teresting one for the reason that it contains pockets of a 
green opaque mineral in which are distributed many fresh 
basaltic hornblendes. The hornblende too is chiefly confined 
to this part, very little being associated with the augite. 
No. 27. The description of No. 12 is quite applicable to 
No. 27 with the exception that there is relatively much more 
augite of the second generation and correspondingly fewer 
augite phenocrysts of the first generation. 
No. 34 agrees very closely with No. 19, with olivine as an 
additional constituent. The olivines are unusually well devel- 
oped, and are easily recognized in the hand specimen, some of 
them being fully one and a half inches in length. 
SlMMAKV of LlTEKATUIiE ON OTHER OOOUKRENOES OK 
Camptonite. 
The name camptonite was first applied by II. Kosenbusch'*' 
to dikes containing augite and basaltic hornblende as the chief 
bisilicates, with variable percentage of phjgioclase, mag- 
netite and accessories. G. W. Hawesf was the first to dis- 
cover these peculiar rocks in this country, near Campton, N. 
*H. RosKNursrn: Pli\ si(ii;rai)liii' iIit inassincn (icstfini'. vol. i. 1.S80, 
p %^. 
fG. W. Hawes: Oh a i^roup of dissiiiiilar iM-iiplivc riicks al L"ain|)t<ii). 
N. H. A. J. S., (3), vol. XVII, p. M, 1879. 
