Anticline in Southern Minnesota. — Focrste. 365 
below the Clinton. It is chiefly a clayey section with occasion- 
al layers of harder clayey limestone. The lower 2 feet of the 
exposure contain Streptelasma rusticum (:= corniculum of 
most authors). The largest specimen found was 8 cm. long. 
In Ohio, Indiana, and north central Kentucky this species was 
common in the Richmond epoch, occurring even in the lowest 
parts of the group. It has not however been discovered in the 
Lorraine. This suggests the Richmond age* of the Ordovi- 
cian exposures along Fishing creek. The other fossils found, 
Hehertella dnuata, Pterinea deniissa, and Byssonychia radi- 
ata, are found both in the Richmond and in the Lorraine 
epochs. 
At the mouth of Forbush creek, the Clinton is underlaid 
by a bluish clayey Ordovician rock, 21 feet thick, containing 
poorly preserved specimens of Cohnnnaria. This fossil is 
common at certain levels in the Richmond formation in Ken- 
tucky and Indiana, but apparently is absent in most of the 
Lorraine. Possibly some of the beds in Nelson and Marion 
counties, Kentucky, which contain Columnaria may be re- 
ferred to the top of the Lorraine. At the mouth of Little Cub 
creek, the Clinton is underlaid by clayey Ordovician rock, 19 
feet thick, in which no fossils were found. 
The reference of the Ordovician rocks immediately beneath 
the Clinton, along Fishing creek, and at the exposures men- 
tioned along the Cumberland river, to the Richmond is there- 
fore merely provisional. 
The total thickness of rock along the upper course of the 
Cumberland river to be referred to the Richm.ond is unknown. 
The Lorraine fonnations. — The next lower rock consists 
of thin bedded clayey calcareous material, in some places 
■ changing to a thin bedded sandy limestone, without fossils. 
At the bend north west of Thomas branch, the exposure of 
this bed is 22 feet thick. On the western side of Horse shoe 
bottom, it measures 28 feet. The total thickness is unknown. 
Beneath the thinbedded rock occurs a massive clayey cal- 
careous rock, usually about 10 feet thick. At the most north- 
ern point on the river, northwest of Thomas branch, this bed 
contains Hetcrospongia subranwsa (identified by E. O. Ul- 
rich ) , and a large form of Platystrophia lynx. The Platystro- 
*J<)HN M. NiCKLKS. The Geology of Cintinnati. Journal, Cincinnati Soc. 
Nat. Hist., vol. xx, No. 2. 1902. 
