90 TWENTY- FIR ST REPORT. 



lowest beds of the Racine of Michigan. These widely separated rocks may 

 occupy the same stratigraphic position. 



The Guelph formation of Ontario, in the opinion of the writer, is to be 

 correlated with certain strata composing the upper part of the Racine forma- 

 tion of Wisconsin and Michigan. This correlation is determined chiefly by the 

 presence of Guelph fossils in the. rocks of the three regions. As jDreviously 

 noted in the first part of this paper, numerous Guelph species were also found 

 to be present in the lower strata of the Racine of Wisconsin (Racine beds, in 

 the restricted sense) by Professors Chamberlain and Whitfield. A few Guelph 

 species, Favosites of. occidens, Amplexus whitfieldi, Pycnostylus guelph&nsis, 

 Poleumita cf. scamn<ita, cf. Pycnomphalus solariaides and Trimerella, sp., have 

 been collected by the writer from strata near and a short distance below the 

 middle of the Racine formation in Michigan. The reason that a larger num- 

 ber of Guelph species have not been found in Michigan is, in the writer's 

 opinion, due to the fact that most of the upper strata of the Racine formation, 

 which would be likely to contain numerous Guelph species, are inaccessible, 

 owing to a covering of glacial soils. Since the Guelph fossils may occur in 

 the lowermost strata of the Racine of Wisconsin and Michigan, which are 

 with little doubt of upper Lockport age, they do not afEord a means of determ- 

 ining the number of feet of Racine strata in the two states that should be cor- 

 related with the Guelph beds of Ontario. 



The Eramosa beds of Ontario may be a correlative of certain strata of 

 the Racine formation. 



It is not the purpose of this paper to indicate all the formations which 

 may be correlated, wholly or in part, with the Racine of Michigan. Such 

 stratigraphic relationships will be considered more extensively by the writer 

 in a forthcoming paper upon the Niagaran deposits of the Northern Peninsula, 

 which will be published by the Michigan Geological and Biological Survey. 



It is necessary to note, 'however, that the Racine formation of Wisconsin 

 and Michigan is closely related in age to the Leclaire limestone of Iowa. 

 Professor Hall* stated that the Racine of Wisconsin " * may be considered 

 indentical with the Leclaire limestone of Iowa, holding precisely the same 

 geological position, and containing some similar if not identical fossils ; * * *." 

 In a communication to the writer. Dr. Ulrich states that there are various rea- 

 sons for believing that the Leclaire and Racine formations are not exactly 

 equivalent. In consideration of Dr. Ulrich's opinion, the names Leclaire and 

 Racine should be employed for the formations in question. If Professor Hall's 

 opinion regarding the equivalency of the two formations should be proven cor- 

 rect, the name Racine, for the uppermost Niagaran formation of Michigan 

 and Wisconsin, would have to be rejected for the older name Leclaire. 



Ann Arbor, Michigan, April, 1919. 



•Hall, James, Report on the geological Survey of the State of Wisconsin, Vol. 1, 

 p. 67, 1862. 



