120 



LIEUTENANT MICHLEr's REPORT. 



llltli meridian. Our trail led up a pretty little valley towards the west for eight miles, when 

 we reached the hase of the ^'Sierra de los Pajaritos" (the Mountain of Little Birds ;) following- 

 up one of the arroyos or gullies of this chain, we were soon locked in on all sides hy high hills ; 

 the ravine through which we continued to wind for four miles hecame rocky, narrow, and 

 difficult to pass, until we reached some small springs, '^Los Ojos de Alizos." At this point we 

 left the arroyo, and. hy clambering up a steep ascent gained the crest of the hills ; riding or 

 walking along it as best we could, and passing from hill to hill, each higher as we advanced, 

 we finally reached the point where the monument stands. The hill on the side of which it is erected 

 is. low compared to the high peaks in its immediate vicinity; its locality is not easily discovered. 

 Our instrument heing placed in position, the azimuth of the new line (69° 19' 45.9" northwest) 

 was measured from a meridian established by assistant Clark ; a large live-oak growing on the 

 adjoining ridge was found to be in the direction of the line, and answered the purpose of a monu- 

 ment, (No. XIX from the Rio Colorado.) Senor A. Diaz, with a party, operated conjointly 

 with us in the prolongation of this line. 



As if in response to our earnest wishes for rain, to be able to continue the work, we had 

 scarcely commenced our labors before the heavens poured down refreshing showers, which we 

 saw with pleasure extended along the line. The commencement of the rainy season is in reality 

 the beginning of spring. The vegetation during the actual months of spring and summer is so 

 parched by the excessively hot suns, that the country present the same appearance as is produced 



The seeds seenj to rest in the earlier 

 part of the season, in order to germinate and beautify the autumn and winter. 



" The Sierra de los Pajaritos" is said to form part of the Arizone mountains, reported to be 

 the richest in Mexico. Many specimens of copper, gold and silver are found on the surface, and 

 they are no doubt rich in ore. The hills are covered with live-oak trees, and are overspread 

 with a rich growth of grama giass ; they are capped by masses of conglomerate rocks. Monu- 



more 



ment XVIII, distant from XIX, a little over three miles, is situated on the same sierra. 



The country here presents a new aspect. Powerful volcanic irruptions have at some earlier 

 period of the world's history produced great disturbances in this part of the earth. Strata of 

 limestone once horizontal, are now curved and bent by the force of this action, and masses of 

 igneous rocks have been upheaved through the fissures opened on the surface. Here you find 

 granite rocks, and near them beds of trap ; 

 fused in one conglomeration. It was impossible to approach the station nearer than three miles 

 with the riding and pack mules ; the instruments had to be transported by hand for that distance 

 up a rugged hill covered with vesicular and scoriaceous rocks. 



from 



XVII 



XVIII. Three 



days were occupied in travelling this short distance. The trail for the first two was over almost 

 impassable mountains ; massive rocks and steep precipices constantly impeded the progress of 

 and turned the party out of its course, making the route circuitous as well as hazardous ; rough 

 ascents were surmounted, steep ravines followed down, and deep gullies passed ; the mules had 

 actually to be drugged along. 



77 



At the end of the second day the party found some small springs— ^' Los Ojos Escondidos 

 the trail to Tubutama, and encamped on them. On the third, the trail was still over high hills, 

 but not so difficult; and some springs— ''Los Ojos de Granizo" 

 ment, were reached. Tlie animals had become so injured and lame by the sharp angular rocks, 

 that they had to be taken into Aribaca to be reshod, and many of them to be replaced by others. 



monu 



