pejoe.J DESCEIPTIVE GEOLOGY — SMITH'S FOEK. 579 



stones, probably some 4,000 feet in all. The soft character of these beds 

 causes them to weather into romidecl hills, in which all the outcrops are 

 obscure. 



As far as seen, the beds resemble very closely those seen on the west 

 side of John Day's Eiver, and they occupy the same relative position. 

 If the conglomerate above is Cretaceous the group must be referred to 

 the Jurassic; if not, it may represent the Cretaceous, while the beds 

 above should be referred to the Laramie Group. The continuation of the 

 section west from Smith's Fork would seem to favor the latter view. 

 Until more fossds are found, I shall refer the beds partly to the Cretaceous 

 and partly to the Jurassic, as just below the shales are limestones contain- 

 ing Jurassic fossds, and on John Day's Eiver the limestones containing 

 Pentacrinus asteriscus were some distance below the Belemnites bed, 

 which was separated from them by reddish shales similar to those above 

 the limestones on Smith's Fork. 



These limestones form a bluff on the Lake branch of Smith's Fork. 

 The exposure of limestones shows a thickness of about 800 feet, and 

 above is a thickness of about 1,800 feet of the reddish shales and sand- 

 stones. Xear the top of the limestones I found : 



Ostrea strigulecula. 



Pentacrinus asteriscus. 



Tancr edict f . 



Undetermined concMfers. 



Undetermined gasteropods. 

 These prove the Jurassic age of the limestones, and they are probably 

 identical with the " Pentacrinus beds " of the section made on John Day's 

 Eiver, near the mouth of McDougal Creek (in the preceding chapter). 

 The limestones form cappings on the slopes of the hills on the east side 

 of the Lake Fork, although they do not reach to the summits, which are 

 mainly of red sandstones. The section as just given in general is as 

 follows, corresponding with the profile in the accompanying plate : 



Section Xo. 25, along Smith's Forte, west from Station 43. 



Base : Thickness in feet, 



1. Bed. sandstones outcropping on Station 43. 



2. Bine limestones containing Jurassic fossils, Pentacrinus, &c 800 



3. Calcareous shales > -. ™ 



4. Eeddish shales and sandstones , ( ' 



5. Space covered with debris of sandstones and shales 4, 000 



6. Conglomerate ? . ™~ 



7. Sandstone shales and sandstones J ' 



8. Blackshales / 1 o^ 



9. Greenish-gray sandstones , $ ' 



Total 11,900 



The dip is 30° westward, as far as Smith's Fork, which is in the syn- 

 clinal depression. 



Between four and five miles above the Forks the stream is formed by 

 two streams, one of which is called the Lake Branch. It comes from the 

 north, whde the Southern Branch comes from the east, draining the region 

 east of Stations 42 and 43. The former is located in the bend of the 

 creek, on a high rounded hill of red sandstones, while station 43 is at the 

 northern end of the same hill. It is on the axis of a fold which is well 

 shown in a high Mil a couple of miles farther north. The axis of the 

 fold appears to have a direction somewhat west of north. Toward the 

 south, however, it appears to curve so as to be north and south, and the 



