520 PLEISTOCENE OF INDIANA AND MICHIGAN. 



Since-cement making became an important business, reports on the production of cement in 

 the United States have been published annually by the United States Geological Survey in Min- 

 eral Resources. These papers are largely statistical and are based on correspondence rather than 

 on field investigations. Several important special reports and papers dealing with the origin, 

 distribution, and utilization of the marl of Michigan and Indiana have also been published, as 

 follows : 



Blatchley, W. S., and Ashley, G. H., The lakes of northern Indiana and their associated marl deposits: Twenty- 

 fifth Ann. Rept. Indiana Dept. Geology and Nat. Res., 1901, pp. 31-321. 



Blatchley, W. S., Cement resources: Thirty-first Ann. Rept. Indiana Dept. Geology and Nat. Res., 1906, pp. 50-61. 



Davis, C. A., A contribution to the natural history of marl: Jour. Geology, vol. 8, 1900, pp. 485-497; vol. 9, 1901, 

 pp. 491-506; Michigan Geol. Survey, vol. 8, pt. 3, 1903, pp. 65-96. 



A remarkable marl lake: Jour. Geology, vol. 8, 1909, pp. 498-503. 



Fall, Delos, Marls and clays in Michigan: Michigan Miner, vol. 3, 1901, No. 11, pp. 11-14; Michigan Geol. Survey, 

 vol. 8, pt. 3, 1903, pp. 343-353. 



Hale, D. J., and others, Marl (bog lime) and its application to the manufacture of Portland cement: Michigan Geol. 

 Survey, vol. 8, pt. 3, 1903, 386 pp. 



Russell, I. C, The Portland cement industry in Michigan: Twenty-second Ann. Rept. U. S, Geol. Survey, pt. 3, 1902, 

 pp. 629-685. 



Marl or bog lime: Ann Arbor folio (No. 155), Geol. Atlas IT. S., U. S. Geol. Survey, 1908, pp. 12-13, 



PEAT. 



Peat is very extensive in northern Indiana and in Michigan on the borders of lakes and in 

 poorly drained situations. It has been made a subject of special investigation by Charles A. 

 Davis 1 and by Arthur E. Taylor. 2 Taylor's report contains the results of numerous borings in a 

 large number of extensive peat bogs of northern Indiana, and includes maps showing the extent 

 of the bogs and their situation in reference to railway transportation Lines. Davis's report con- 

 tains fewer data concerning the thickness of peat in the bogs of Michigan but goes more fully into 

 the origin and the ecology of peat. He discusses also the use of peat as fuel, arguing that though 

 peat is unlikely to be utilized to more than a slight extent in competition with coal, peat bogs will 

 yield quick and sure returns if they are developed in a small way for local markets rather than 

 on a large scale in competition with better-known and more widely used fuels. "A relatively 

 small bog, a small hi vestment, and a local market, with a limited requirement in quantity should 

 make a combination which should be satisfactory to the owner and the investor, who could then 

 afford to give his customers a fair price, which should run considerably below that paid for ordi- 

 nary fuel, and still give good profits." Davis's report also describes peat-working machinery in 

 considerable detail. 



In addition to these two large reports Taylor 3 and Davis 4 have each published short papers 

 on this subject. 



CLAY. 



The extensive till sheets of Indiana and Michigan are utilized to some extent for brick and 

 tile, but are in most places too full of stony and sandy material to be suitable even for these 

 products. The clay of chief commercial value in these States is a water deposit laid down either 

 in lakes or in slack drainage. Loess deposits laid down by wind are important in southern 

 Indiana, where also much of the alluvial material, being derived by wash from bordering loess, 

 is suitable for use in some of the clay industries. 



The thickest deposits of clay on the beds of the great glacial lakes are found in depressions 

 protected against disturbance by waves. Thus in the Erie-Maumee basin deposits are thick in 

 the area covered by Defiance Bay of Lake Whittlesey west of the Defiance moraine, and are very 

 light on the submerged portion of the moraine and the plain to the east. The deposits become 

 thicker, however, west of Napoleon and near Toledo and are drawn upon extensively for use in 

 clay industries and for the manufacture of Portland cement. In the Rouge River basin west of 



1 Ann. Rept. Michigan Geol. Survey for 1906, 1907, 302 pp. 



2 Thirty-first Ann. Rept. Indiana Dept. Geol. and Nat. Res., 19U3, 225 pp. 



' Indiana peat, its origin and value: Jour. Am. Peat Soe., vol. 2, 1909, pp. 30-33, 64-67. 

 * Ann Arbor folio (No. 155), Geol. Atlas TJ. S., TJ. S. Geol. Survey, 1908, pp. 12-13. 



