PAPERS OX GEOGRAPHY AND GEOLOGY 241 



Tlie following species of fossils were collected from the 

 lower portion of the shale exposed in the railroad cut at 

 Scales Mound. These are peculiar in that they are all 

 of small size, and consist mainly of mollusks. Brachio- 

 pods, and especially bryozoa, are exceedingly rare. 



LIST OF FOSSILS FROM THE LOWER PART OF THE MAQUO- 

 KETA SHALE AT SCALES MOUND 



Dalnianella testudinaria (Dalnian) (c) 



Zygospira niodesta Hall (c) Richmond 



Ctenodonta fecunda (Hall) (c) 



Ctenodonta obliqua (Hall) (c) 



Clidophorus neglectus Hall (c) 



Bellerophon sp. 



Liospira rnicula (Hall) (e) 



Lophospira pulchella Ulrich and Scofield (c) 



Pleurotomaria depauperata (Hall) (c) 



Orthoceras sociale Hall (a) 



The fauna listed above is conspicuous in that it is not 

 a typical Richmond fauna. (July one of the species 

 Zygospira modesta. is listed by Comings from the Rich- 

 mond strata of Indiana, and that has a wide range, both 

 geographical and vertical, and is of no value in strati- 

 graphy. The fauna resembles the lower Maquoketa 

 fauna found near Graf, in Dubuque County, Iowa, and 

 doubtless represents a corresponding horizon. 



In the vicinity of Scales Mound, the Maquoketa forma- 

 tion, above the shale exposed in the railroad cut, consists 

 of 50 to 75 feet of bluish-gray, non fossiliferous shale in 

 which are occasional thin bands of earthy dolomite. 

 This is overlain by about 2S feet of alternating layers of 

 calcareous shale and limestone that contain numerous 

 fossils among which are many bryozoa. These upper, 

 calcareous and fossiliferous beds outcrop along the 

 wagon road two and one-half miles northeast of Scales 

 Mound, near the west side of sec. 19. T. 29 N., R. 3 E. 

 from which locality the fossils listed below were col- 

 lected. 



LIST OF FOSSILS FROM UPPER MAQUOKETA STRATA 

 MILES NORTHEAST OF SCALES MOUND 



Amplexopora sp. (a) 



Batostoma sp. (a) 



Bythopora meeki (James) (r) W. L. Wh. 



Constellaria polystoniella (Nich.) (r-c) W. L. 



Corynotrypa inflata (Ulr.) (c) Richmond 



Dicranopora emacerata (Nich.) (r) Richmond 



