196 



UliUl.O- 



L.ViJiAUS. 



ing pictures of sliadef! 

 ■^J'usiiar and t]ie 

 Bftedley of ploa?^ 

 back to with : 

 meager. N< 

 result of r - 

 weatlK"  

 of%vl 



it pari <>' 



I ^lopiug banks,' with distant views of the 



'] of the Sevier Plateau, bonibine to produce a 



ind experiences which will always be looked 



As a field of geological study it is in great part 



ilsen a bit of loo^l curiosity is excited by a curious 



ire, by remains of. small lake deposits, by the curious 



ixvs, by some strange freak of the old lava flows, none 



' places here. Broad facts are comparatively few. 



most noteworthy is the succession of eruptions. In the 



thfi Markdgunt the oldest eniptions observed were andesitic. 



• in a disconnected way iu i or ravines of the cen- 



elsewher* 



subsequent 



jh of fl 



;■ ','1 i-jiai LTuj-.-iuiifc if iS iioi pv'afeiuie lo 



caftons are found in the central part of 



js of dark andesitic lava, and areas are 



snrfiice erosion has removed the later rocks and 



y event, whether generally or discontiuu- 



mass of this rock is very great. No propylitic erup- 



I in the Mark^gunt. 



great masses of ti-achyte. Ov- aterpor- 



vrkdgunttliese are the sur&ee i '' \ 



that of the andesiles, •tvhicli theyusuaii} cover, 



■en they appear txt bo the dominant rock, and 



t they are so. On the whole, the varieties of 



a tiie Markdgunt than in the more eastern pla- 



 ir number is still \ery great. The least com- 



Uc; but the augitic trachytes are abundant, 



he commonest of ail is a highly porphyritic argillold variety. The 



consists of iiplish fine base, resembling a rather rough 



to, holding cry.suiia oi paque orthoclase. One of its most per- 



which is very peculiar. Most volcanic 

 .r,r,- oven or gently rounded though 



the r: 



laid ; 

 ousU 



tions have h' 

 N^ext in  

 tiun of the e> 

 their volume m; 

 but being more ! 

 I incline to the 

 trachyte are lesh 

 teaus of th • distxi 

 ttjon variet\ is the I 



