486 IOWA ACADEMY OF SCIENCE Vol. XXVI, 1919 



the Independence. A well-known example is the Kenwood beds of 

 Norton* in Linn county. 



The fossiliferous facies of the formation has unfortunately been 

 too meagerly. known. Some years ago a typical Independence fossil, 

 Douvillina arcuata, was brought up among well borings from a 

 depth of one hundred feet near Walker.'^ Other borings have 

 encountered shaly carbonaceous strata, believed to be the Indepen- 

 dence from their position beneath the limestones. These finds, to- 

 gether with an outcrop that was soon covered by slump near Linn 

 Junction found by Professor Norton several years ago,'' prove that 

 the dark facies has a fairly wide but perhaps irregular distribution. 

 In spite of the readiness with which the unindurated shale slumps 

 and is covered up it has been hoped that sooner or later natural ex- 

 posures would be found. Fortunately a number of such outcrops 

 occupying anomalous stratigraphic positions have been discovered. 



In 1916-17, Mr. Merrill A. Stainbrook, one of the writer's pupils 

 in historical geology, discovered a fossiliferous shale along Lime 

 creek, ^ a tributary of Cedar river in the southwest corner of Bu- 

 chanan county. The fossils which he collected are typical Inde- 

 pendence forms. In company with Mr. Stainbrook, the writer vis- 

 ited the outcrop in the fall of 1917. Since that time the young man 

 has found two other exposures which he reported by letter just 

 before leaving for training camp. Later the three outcrops were 

 studied in company with Professor Norton, of Cornell College. 



Exposure No. 1. — Here the shale occurs in a sharp bend or re- 

 entrant on the right bank of the creek in the northwest quarter of 

 section 26, about a mile northeast of the town of Brandon. Under- 

 cutting by the stream at this point has exposed from one to six feet 

 of the shale for a distance of fifty to sixty feet. By digging back 

 the sod above the shale the latter was traced about five feet higher 

 up the bank, making a total thickness above the water of at least 

 eleven feet. The digging, however, afiforded no clue to the indurated 

 beds, if any, which may overlie the shale at this point. The immedi- 

 ate bank of the stream here is close to twenty feet high while back 

 from this the surface rises gradually to a height of nearly sixty feet. 

 The outcrop is flanked by exposures of limestone ; on the downstream 

 side the shale and limestone are separated by about three feet of 

 weathered shale intermingled with blocks and fragments of lime- 



*Iowa Qeol. Survey, Vol. IV, pp. 156, 157, 1895. 



»Iowa Geol. Survey Vol. IV, p. 157, 1895. 



"Private communication. 



'This fifteen mile tributary of Cedar river is not to be confused witli a stream 

 of the same name in Cerro Gordo and Floyd counties. It is along- the latter 

 that the Lime Creek shale, mentioned later in this article, is found. 



