794 REGINALD ALDWORTH DALY 
evidence. The existence of zones of passage between the por- 
phyritic granite and the schists with which it comes in contact 
is a fairly common phenomenon in the case of stocks of plainly 
eruptive material. Such transitions then form no inherent 
objection to a similar origin in this instance. 
2. The intrusions necessarily took place under great depth of 
strata. The latter were elevated by the last great period of White 
Mountain flexure and were practically holocrystalline products 
of the consequent metamorphism before the porphyritic granite 
was intruded. The subsequent disturbance of the greatest inter- 
est to us in this connection is that which caused the porphyritic 
granite to assume the parallel structure of flowage under differ- 
ential stress analogous to that of the Himalayan and Alpine 
central granites. Since that time, the force operating on the 
terranes has been relatively slight. It has not sufficed to rub 
out completely, in any part, this initial structure of the por- 
phyritic granite. 
3. The molten rock entered the overlying schists in an irreg- 
ular fashion but in general followed the regional line of strike of 
the White Mountain district. 
4. Various considerations lead us to believe that the three 
areas of porphyritic granite described are virtually contempo- 
raneous. They are, in every case, post-Devonian in age, — how 
much younger is unknown. Not being a basal formation, the 
terrane loses much of its value in an elaboration of the strati- 
graphic sequence and areconstruction of the New Hampshire 
geological scale is necessary. 
5. The porphyritic granite adds its testimony to the value of 
the opinion recently formulated among geologists that a highly 
important class of gneisses owes its parallel structure to fluxional 
movement. And it has the other general kind of interest in 
exemplifying the truth of Barrois’ prophecy ‘‘que les terrains 
paléozoiques sont destinés a s’étendre de plus en plus sur les 
cartes géologiques aux depens des terrains primitifs.”’ 
REGINALD ALDWORTH DALY. 
HARVARD UNIVERSITY. 
