xliv THE PALEONTOLOGY OF MINNESOTA. 



for the column 1, that the common species are 28 per cent, of the smaller fauna, i. e., of 

 the total possible number; and for column 2, the much larger proportion of 68 per cent. 



Such comparison of the Hudson River and Trenton shows 28 common species, a 

 slightly larger number than comes in column 1, but the greater number of species in the 

 Trenton than in the Galena accounts for this increase, while yet there is in this last compar- 

 ison a less close affinity than in the first. 



W. H. Pratt. 



1883. An artesian well at Moline (111.), by W. H. PRATT, Proc. Davenport Academy 

 of Natural Sciences, vol. in, p. 181. Read Nov. 25, 1881. This well gives the depth and 

 thickness of the Maquoketa shales, showing a great increase toward the east from their 

 typical locality. They are 395 feet below the surface, and 220 feet thick. 



Jos. F. James. 



1886. Description of a new species of Gomphoceras, from the Trenton of Wisconsin, by 

 PROF. Jos. F. JAMES. Journal of the Cincinnati Society of Natural History; Jan., 1886. 

 Describes Gomphoceras powers!, from Beloit, Wis. 



George M. Dawson 



1886. On certain borings in Manitoba and the Northwest Territory, by GEORGE M. 

 DAWSON. Trans. Roy. Soc. Canada, 1886, vol. iv. 



In this paper certain shales passed through in the Rosenfeld deep well are regarded 

 as belonging to the Maquoketa, amounting to 352 feet, and the underlying cream-colored 

 limestone and red shale, amounting to 880 feet, are assigned to the Galena and the Trenton. 

 No fossils were obtained. This interpretation of this well is quite different from that given 

 by one of the writers in the thirteenth report of the Minnesota survey, pp. 40-46 (for 1884), 

 of the salt well at Humbolt, Minn., situated about twenty-five miles toward the southeast. 

 The Rosenfeld well section is also published, without comment, in the fourteenth report of 



the Minnesota survey, p. 15. 



Samuel Calvin. 



1888. Notes on the formations passed through in boring the deep well at Washington, 

 Iowa., by SAMUEL CALVIN; American Geologist, vol. i, p. 28; Jan., 1888. 



At the depth of 702 feet the Hudson River shales were struck in this well, with a 

 thickness of 91 feet They were immediately beneath a sandstone 170 feet thick which 

 was referred to the Niagara period. The Galena was found at 803 feet, extending to 963 

 feet. This is a grayish limestone, but not a dolomyte. The Trenton, with bits of carbon- 

 aceous shale, and quite rich in bituminous matter, was encountered at the depth of 1020 

 feet, and extended to 1095 feet, with some arenaceous shale and sandstone near the bot 

 ton?. At 1100 feet the St. Peter sandstone appeared. 



J. F. WJiiteaves. 



1889. Descriptions of eight new species of fossils from the Cambro- Silurian rocks of Man 

 itoba, by J. P. WHITEAVES, Trans. Royal Soc., Canada, 1889, vol. vii. Plates xii and xiii. 



