Explorations in Colorado. 163 
being about six thousand square miles. The geology of this dis- 
triét is comparatively simple, there being no great uplifts, nor 
_ many local disturbances. The sedimentary beds are all included 
under the Carboniferous, Red beds (Triassic ?), Jurassic, and 
= Cretaceous series. On August 15th, the work was brought sud- 
denly to a close by the Indians. 
The work of the fourth division, directed by G. R. Bechler, 
_ extended over a large area, situated from the foot-hills of the 
Rocky Mountains to the Upper Arkansas and Eagle rivers, and 
from a point six miles south of Pike’s Peak to within fifteen miles 
of Long’s Peak, including the great mining industries of Col- 
orado. 
The party under Mr. Gardner had made but little progress 
when it was prevented from doing further work by the Indians. 
One of the stations occupied was very important, namely, the 
Sierra la Sal Mountain, which enabled Mr. Gardner to secure an 
excellent set of observations, thus extending the triangulation far 
into Utah, and connecting the eastern work of the survey with 
the great Colorado River of the West. i 
= The trip of Mr. Jackson, the photographer of the expedition, 
to the southwestern portion of Colorado renewed the work of 
1874 on the ancient ruins north of the present Moquis Pueblos. 
Interesting archæological discoveries in the upper San Juan Mesa 
Verd@find La Plate regions were made by Mr. W. H. Holmes, 
m addition to his geological work. The ruins occurred only in 
_ “ese cations which had alluvial bottoms. A strip of bottom 
j land only fifty yards in width at the bottom of the deep cañons 
Would yield maize enough to subsist quite a town. The supposi- 
4 tion that they belonged to an agricultural people is strengthened by 
the fact that in the vicinity of any group of ruins there are also a 
_ humber of little « cubby-holes,” too small for habitations, but very 
| evidently intended for “caches ” or granaries, and the large towns 
q Contain small apartments that must have been designed for the 
_ SMeuse. In one place where grass, cedar, and artemisia flour- 
Ash, and there is most excellent grazing land, these people must 
have had herds of sheep or goats which they brought up here to 
: graze during the winter, just as the Ute and Navajos do at the 
Rant: time ; and the towers 80 frequent in this region were 
_ Probably built as places of refuge or residence for the herders. 
Pon the faces of rock near one of these ruins is an inscription 
— “Mpped in with a sharp-pointed instrument, and covering some 
‘IXty square feet of surface. Figures of goats, lizards, and hu- 
