peale.1 DESCEIPTIVE GEOLOGY BEAE EIVEE AEEA. 609 



Biver is a sluggish stream with a muddy bed. The water is somewhat 

 alkaliue, as it is in most of the wells sunk in the valley. The three 

 principal streams that unite below Malade City to form the river are 

 Devil Creek, Mill Creek, and the Little Malade. The first of these rises 

 in the south end of the Bannack Eange, opposite the head of Marsh 

 Creek. On the east side of this creek the White Tertiary beds outcrop. 

 The upper lake terrace extends almost to the divide, which, as Professor 

 Bradley suggests, might have been a point of dribbling outflow for the 

 waters of the great lake when at its highest level. It must have been 

 when the lake in Marsh Creek Valley was at the level indicated by the 

 upper terrace, and this divide was a point of connection between the 

 two lakes, as the elevation of the divide is lowerthan that of the highest 

 terrace in Marsh Valley. 



The beds at the southern end of the Bannack Bange are probably the 

 continuation of those on the east side of the valley, as Professor Bradley 

 speaks of finding characteristic fossils in the southern end of it. 



The upper valley of the Malade has an elevation of about 4,700 feet, and 

 is filled with soft, sandy, and marly beds. On the Little Malade there are 

 bluffs of these beds about 50 feet high. Near Plymouth I found in these 

 beds specimens of a Limncm. Whether these beds are contemporaneous 

 with, those of Cache Valley or later I don't know, but they are more 

 alkaline, and if the lake filled the valley after that of Cache Valley was 

 drained, they are probably more modern. There are hot springs deposits 

 at various points, and many of the springs stdl exist with slightly warm 

 water. 



As we have already seen, the Tertiary beds outcrop on the east side 

 of the valley. On the west I did not see them. They are probably 

 present beneath the more modern deposits. On some old maps the 

 Malade is known as Boseaux or Beed Creek. 



At Hampton's Bridge of Bear Biver the Bear is flowing southwest, 

 but it now turns southward, and flows parallel to the Malade sout h be- 

 yond our district. Where they cross our south line they are only about 

 a mile from each other. From this point the streams are both very 

 sluggish. The river terraces on the Bear at the bridge are well marked. 



BLUE SPRING HILLS. 



The Blue Spring Hills he on the west side of Malade Valley. Three 

 topographical stations were made on them, the summit of the range 

 forming the western line of the work done by us. The rocks are all 

 Carboniferous, with western dips. Station 136 was on the hills west ot 

 the head of the Malade. Limestones outcrop on these hills dipping 15° 

 south 27° west. Fossils were obtained from two layers on the eastern 

 slopes of the hills. The following are the fossils : 



Layer No. 1 — Zaphrcntis f 



Fenestella . 



Rhombopora lepidodendroides. 

 Layer No. 2 — Productus pratteniianus. 

 Rhynclionella uta. 

 Spirifer striatus. 

 South of Samaria, the following were found : 

 Productus costatus var. 



Euomphalus f 



Aulopora f 



Zaphrentis f 



39 G s 



