NOTES ON THE STRATIGRAPHY OF THE RACINE FORMATION OF 

 THE NORTHERN PENINSULA OF MICHIGAN.' 



Q. M. EIILEBS. 



The use of the name Racine is suggested by the writer for the thick- 

 bedded, white dolomite formation at the top of the Niagaran of the Northern 

 Peninsula, which heretofore has been designated as Guelph and Engadine. 

 Dr. A. C. Lane^ in 1908 referred to the formation as Guelph, correlating it 

 with the formation of that name in Ontario. In 1915, Mr. R. A. Smith' pro- 

 visionally named the formation Engadine and indicated its probable correla- 

 tion with the Guelph. In the following year, the name Engadine was accepted 

 by the Michigan Geological and Biological Survey^ and the formation definitely 

 correlated with the Guelph. Recent studies by the writer indicate, however, 

 that the Engadine dolomite includes strata which are older than Guelph as 

 well as strata of Guelph age. The name Guelph, since it was not proposed to 

 include these older strata, is therefore inappropriate for this formation. The 

 Engadine formation, furthermore, is with little doubt continuous with the 

 formation in eastern Wisconsin which was named Racine by Professor James 

 Hall° in 1862. The name Engadine, since it is applied to a formation previ- 

 ously designated as Racine, should therefore be rejected. 



The division of the Racine of Wisconsin into the Guelph and Racine by 

 Professors Chamberlain and Whitfield is apparently unwarranted. These 

 writers" applied the name Guelph to the uppermost strata of the Racine forma- 

 tion of this state, upon finding that they contained a fauna very similar to 

 that of the Guelph formation of Ontario. They' retained the name Racine 

 only for the lower strata of the formation, designated by that name by Pro- 

 fessor Hall. When making this division. Professors Chamberlain and Whit- 

 field' recognized that the Wisconsin Guelph and Racine, as used in their 

 restricted sense, do not differ essentially in lithologic character and that num- 

 erous Guelph species are present in the Racine beds. In a communication to 

 the writer, Dr. E. O. Ulrich of the United States Geological Survey states 

 that, so far as he knows, there is no stratigraphic nor paleontologic break 



'Published with the permission of the Director of the Michigan Geological and 

 Biological Survey. 



^Lane, A. C, Ann. Kept, for 1908, Michigan Geol. Survey, pp. 56-57. 



^Smith, R. A., Pub. 21, Geol. Ser. 17, Michigan Geol. and Biol. Survey, pp. 150- 

 151 191.5. 



' "Allen, R. C, Smith, R. A., and others, Geological Map of Michigan : — Pub. 23, 

 Michigan Geol. and JMol. Survey, 1916. 



^Hall, James, Report on the geological survey of the State of Wisconsin, Vol. 1, 

 p. 67, .1862. 



«Chamberlain, T. C. and Whitfield, R. P., Geology of Wisconsin, Vol. 2, pp. 335- 

 336, 1878. 



'Op. cit. 



^Op. cit., p. 377 and faunal lists, pp. 384-389. 



21st Mich. Acad. Sci, Kept., 1919. 



