GEOLOGY OF LITTLE ROCKY MOUNTAINS 405 
and plains country about the mountains. The following, Table I, 
shows the general sequence of the sedimentary series. No 
Lower Cambrian, Upper Carboniferous, or Triassic rocks occur 
in the region. The oldest unaltered stratified rocks are of 
Middle Cambrian age. The base of the sedimentary series is a 
fine, dense quartzite of a pale pink or flesh color, which is some- 
times a conglomerate at the base, the pebbles being of clear or 
slightly turbid quartz. Scolthus borings were observed in this 
bed, but no fossils were found. Overlying this the lowest and 
oldest of the unaltered sedimentary rocks is a series of shales 
of greenish or reddish colors, of which no good exposures were 
found. 
WAN BILE, Ile 
Cretaceous, - - Sandstones and shales. 
Jurassic, - - - Limestones. 
{ Limestones; massive, very heavily bedded, 
Carboniferous : lee, While tock 
, 7 Limestones, laminated, ochreous stained, 
; | forming reddish exposures. 
Devonian? - - Limestones ; thinly bedded, gray. 
Sine: , { Limestones; dark gray and black, fetid, 
; ( mottled beds. 
( Alternating micaceous shales, impure sand- 
| stones, glauconitic limestone, and lime- 
Cambrian, - - + stone conglomerate. 
| Shales. 
| Quartzite. 
Algonkian or Archean, Crystalline schists, gneiss and quartzite. 
Fine sections of the limestones are to be seen in almost all 
of the canyons cut by the mountain streams. The canyon of 
Peoples Creek, along the channel of which the road from St. 
Paul’s Mission to Landusky has been built, shows especially 
good exposures of these rocks. The beds dip at 10° down 
stream and are cut in a narrow gorge. The Cambrian rocks are 
not well exposed, but have been eroded into a little park or 
valley between the higher porphyry slopes and the limestone 
plateau. 
Near Landusky the Paleozoic limestones, though prominent 
features of the landscape, do not present good sections, but the 
