BAIN] CABBONIFEROUS ROCKS. 23 



district. Mr. Ulrich recognizes these beds as the equivalents of 

 those to which Shiimard originally gave the name Ste. Genevieve in 

 Missouri, and that name is accordingly applied to them here. 



Princeton limestone is a name for the beds which has obtained a 

 certain amount of local use, but which is considered synonymous 

 with Ste. Genevieve. On account, principally, of the affinities of its 

 fauna, Mr. Ulrich regards the Ste. Genevieve as the base of the 

 Chester group. Mr. Keyes « considered it to belong to the St. Louis, 

 to which it is much more closely related lithologically than to the 

 overlying Cypress sandstone. 



CYPBESS SANDSTONE. 



Ghararter and thickness. — Above the Ste. Genevieve is a massive to 

 lieavy-bedded sandstone almost wholl}^ quartzose. So far as has 

 been observed, this formation contains very little shale or argillaceous 

 matter. The lower portion of the sandstone is characteristically 

 heavy bedded, but the upper portion is somewhat thinner bedded to 

 flaggy. Near the middle is frequently a thin bed of chert-bearing 

 limestone carrying a characteristic fauna. 



The thickness of the formation in this area may be estimated at 

 80 to 100 feet. 



Distrihiition and relations. — No attempt has been made in the maps 

 so far prepared to separate the Cypress from the Tribune and Birds- 

 ville. It would be possible to do so only on good base maps and with 

 time for detailed stu.dies. The Cypress sandstone is doubtless pres- 

 ent at many points in both Hardin and Pope counties, but may easily 

 be confused with certain phases of both the Birdsville and the Mans- 

 field. It may, however, be seen ty]:)ically developed at l)oth Rosi- 

 clare and Shetlerville. At the former localit}^ it caps the Ste. 

 Genevieve limestone in Downeys Blult', the basal heavy-bedded sand- 

 stone being present. At Shetlerville these basal beds are less typ- 

 ically exposed, but the thin limestone member and the overlying 

 flaggy sandstone were recognized by Mr. Ulrich. 



iVanie and correlation. — Cypress sandstone is a name originally 

 proposed by Engelmann ^ for this formation. Equivalent beds have 

 been called Big Clifty sandstone by Mr. Norwood,*' and Aux Vases by 

 Mr. Keyes.'' In the early geologic literature of the region most of 

 the exposures of this sandstone were referred to the " Ferruginous 

 sandstone," a term also applied at times to what is here called the 

 Mansfield sandstone. 



, " Geol. Survey Missouri, vol. 4, 1894, pp. SO, 76. 



"Trans. St. Louis Acad. Scl., vol. 2, p. 189. 

 " Geol. Survey Kentucky, new ser., vol. 1, p. 369. 

 " Bull. Geol. Soc. America, vol. 3, p. 296. 



