I 
Hsyden Geological Purvey. 
Headwaters of tire Rio Grande—»nc* 
eeurnl Operations. 
The following private letter from Mr. W. 
H. Holmes, assistant geologist connected 
with the division of the above survey, now 
engaged in exploring the southwestern por - 
tion of Colorado, to Dr. Hayden, the geolo¬ 
gist in charge, will be read with interest: 
Head of Rio Gbande, September 7,1876. 
— We are camped on the Rio Grande so near, 
the source that it is only a small stream,—so 
small that a man might step over it. Since 
parting with you at the base of the Sierra 
Blanca we have made two great summits 
without missing a day, and making altogether 
the neatest connection throughout that can 
be imagined. You desired me to give full 
details, but 1 may say truly to begin with 
that what we have seen and done belongs 
rather to the generals than to the particulars. 
We have seen a country which is built on a 
large scale, and in a large or gene, al way 
we have seen it. Each day s work 
has been full. The second day after parting 
with you, we reached Del Norte, leaving be¬ 
hind us the little praised yet interesting and 
beautiful San Luis park. Oa the following 
morning we organised a small party tor a 
side trip to the Summit district. We found 
a good wagon roa > leading up to the mines 
—some twenty-five miles—and passed on be¬ 
yond to the base of a mountain (called by 
Clarke, of the Wheeler party. Mount Blaine), 
making a march of nearly forty miles. On 
this peak Mr. Wilson wished to make one of 
the primary triangulation stations. 
Next morning, September 1, we were on 
the summit by 10 o’clock. Mr. Wilson suc¬ 
ceeded in making a fair set of observations, 
and I spent a couple of hours making a de- j 
tailed sketch ot the Trachytio mountain re¬ 
gion to the south. This region is the south¬ 
ern extension cf the Summit plateau, (on 
which is situated the mining district,) and 
lies between the Rio Grande basin on the 
east and the upper Sau Juan valley on the 
west. The entire plateau is high, most of it 
being above or near Umber line, and is rather 
higher on the hordes, especially so on the 
San Juan side. We thus have a large area 
which is but poorly drained . and 
hence retains much water and abounds in 
immense tracts of bog or swamp lands. Tht 
wetter portions in the broad upland valleys 
are covered with a dense growth of swamp 
grasses and willow bushes, while the drier 
parts have considerable fine forest. Oar 
sta ion, which reaohes an elevation of 13,000 
foet, is situated on the con inental divide, 
but lies on the west side of the plateau over¬ 
looking the eafions of the upper San Juan. 
South of it is Banded mountain, occupying 
the center of the great group shown in my 
sketch. To the west and northwest is spread 
farth one of the grandest mountain land¬ 
scapes that 1 have ever had the good fortune 
to behold. Under us are the beep rock- 
walled and timbered eafions. Rising beyond 
these, with pioturesque forms and fine colors, 
is the first group of the San Juan mountains, 
of which the Rio Grande pyramid seems to 
be the culmina ing point. Beyond this, and 
towering above is the second group—the fa¬ 
mous quartzites—presenting an astounding 
array oi lofty needle-like points, and 
| combed ridges. This group 1 have since 
i s en from a nearer point, and shall 
subsequently describe more fully. .The 
view to the north and east present nothing 
- out of the ordinary run of moun'ain scenery. 
The Sangre de Cristo range could be seen be¬ 
yond the San Luis Valley and Saguache and 
Uncompahgre ranges were in plain sight to 
the north. The formations here are totally 
trachytio and together with the very valu¬ 
able mines of the district will doubtless be 
fully described by Dr. Endlich in his report 
for 1876. 
Having successfully finished our work in 
this district, we set out for the Rio Grande, 
passing down a small branch to the south 
fork and thence reaching the main camp six¬ 
teen miles above Del Norte. In three days 
we had traveled upwards of eighty miles, be¬ 
sides making a successful high mountain 
station. Our next station was to be the Rio 
Grande pyramid. On September 3, we 
marched about twenty-five miles up the Rio 
Grande, and on the following day reached 
the base of the peak, thirty miles farther. 
Our eamp was near the source of the Pinos 
river, a tributary of the San Juan. An In¬ 
dian trail runs over the pass. By this route 
we entered the Sau Juan basin last year. 
On the morning of the 5th we aaos-ndt d the 
pyramid. At timber-line we encountered a 
severe rain and snow storm. The sky cleared 
again «oon, and by 11 o’cloek we were on 
j the summit, but just in time to encounter 
I another and much more sivere snow storm. 
For i early an tour we lay on the leeward 
side of a small monument, trying to keep 
warm and congratulating ourselves that we 
would know the way up tomorrow Soon 
after 12 the clouds began to break, and 
glimpses of the mountain could be had. By 
1 o’clock we were at work, and as the differ- 
ei ent groups came out partially <r entirely, 
we snatched, as it were, from the jealous aud 
unwilling storm our observations and draw 
ings. Ti e one a reat feature of the day, to 
j me, was the view of ths quartzite group, 
vynich lay imrn diatsiy to the west. The 
vji w is one in a thousand, and y ou would 
| have been lost in admiration and amazement. 
i You have seen a thousand panoramas, but 
| none like this. I predict that when you see 
my sketch you will ba highly pleased. But 
what are these mountains like? Ifyousbould, 
in your imagination,put togs her in one small 
group, perhaps twelve miles square, all the 
heights and depths, the rugged precipices 
and polished faces of rock and all th8 sharp 
pinnacles and deeply indented crests and 
twenty times the inaccessible summits that 
both of us have ever seen you would not 
have a picture equal to this. Words can 
hardly express sufficient to enable me speak 
in hyperbole of this unparaleil d group of 
peaks. My poor sketch made through the j 
rents in the clouds will tell, you best what 
they are like and a sketch of such a subject 
must be but a feeble, a very feeble, expres¬ 
sion of the truth as you must fully know. 
Beyond this group to the south appear the 
a a moun tains; and to the north the 
Ban Miguel and Unoompahgre. The great 
summit of the latter range impresses one 
greatly with its height and if appearances 
count for anything the great Blanca has a 
“«««ou s rival. The mountains to the 
north have a covering of snow, but other- 
wise attract but little notice from this point. 
I he Rio Grande pyramid is a fine 
peak named so on occount of its 
symmetric pyramidal shape. It is com- 
posed entirely of trachyte and is easy 
of access. The surrounding valleys o eafions 
are cut sharp and deep in the massive bedded 
trachyte. The character of the country is 
very like th8 East Yellowstone and Clark's 
-Cork region. 
We are now one day's march from the 
base of the pyramid and to-morrow shall 
pass through Silverton ou our way to La 
Fiata. I hope to get another look into the 
quartzites to morrow morning. I have told 
you but little and that in a very unscientific 
way, but I hope you will excuse me. The 
party are all well and in good spirits. Five I 
peaks are done and five or six yet to do. 
. W. H. H. j 
