62 Col. McMahon—Granite of the Himalayas. 
One remark, however, in Mr. Oldham’s article, tempts me to offer 
a few words of explanation in continuation of my last paper in the 
GxrotocicaL Macazine. Speaking of the gneissose-granite, Mr. 
Oldham expresses his belief “that the very slight foliation of the 
larger masses is principally a fluxion structure, while the more 
developed structure of the thinner bands, and near the margins of 
the larger masses, was produced in the solid but séill heated granite 
[the italics are mine] by the same causes—whatever they be—that 
led to the foliation of the adjacent sedimentary beds;” and in a 
footnote he remarks; “ In 1884 Colonel McMahon seems to have 
held an opinion somewhat similar to this (see Records Geol. Surv. 
India, vol. xvil. p. 72), but so far as I can understand his paper in 
the May Number of this MaGazinn, he has now abandoned it.” 
I hoped that I had made my meaning sufficiently clear; but as this 
does not appear to have been the case, a few explanatory remarks may 
not be out of place. The passage in my paper published in the Records 
Geol. Surv. India referred to runs as follows :—‘“‘ The conclusion at 
which I have arrived, on a consideration of all the facts of the case, 
is that the invasion of previously metamorphosed strata by gneissose 
granite, combined with the pseudo-foliation of the latter due to the 
pressure of hard strata on a partially cooled and imperfectly viscid 
rock, has imparted to the intruded rock the superficial appearance of 
being a member of the same metamorphic series as the schists and 
slates into which it has intruded. There is no inconsistency, I would 
point out in conclusion, in supposing that the rock which gives 
evidence of having passed through a stage of aqueo-igneous fusion 
was partially cooled and semi-viscid when’ actually intruded into 
the schists. Observation in our own time shows that there are 
pauses and long intervals in volcanic action; and doubtless similar 
pauses took place in plutonic action during which the cooling and 
partial consolidation of igneous masses went on and the larger por- 
phyritic crystals found in many of them were formed. The subse- 
quent motion of a partially consolidated viscid rock and its intrusion 
as a sheet between hard strata, or between the walls of a fault, 
would, it seems to me, naturally produce parallelism of structure, or 
pseudo-foliation, as long ago pointed out by Scrope and Naumann.” 
I have not gone back one iota from the view expressed in the 
above extract, and I am ata loss to understand why I should have 
been supposed to have done so. The observations given at pp. 219, 
220, of the 1887 volume of this Macazing, seem to me to be 
merely a detailed explanation of the view more briefly expressed in 
the above extract. In the latter three conditions are noted; the 
partial consolidation of the granite before it was moved into place, 
traction action on the granite when it was squeezed into position ; 
and the ‘“‘ pressure of hard strata” upon the intruded mass. 
That partial consolidation had set in before the granite was 
moved into its present position seems implied by the pronounced 
porphyritic character of the rock. ‘All the facts connected with 
1 Inthe Records the word is where—a senseless alteration of the text due to the 
Indian printer’s devil. 
