REVIEWS ' 593 



Price, J. A. and Shaaf, Albert. S^y Run and Poinsett Lake Bottoms, 



and the Abandoned Meanders of Spy Run Creek. Proc. Indiana Acad. 



Sci. for IQOO, pp, 179-84, iQOi. 



The features here discussed appear in a small valley one and one-half miles north- 

 west of Fort Wayne, and north of the Fort Wayne outlet of Lake Maumee. It is 

 thought that lakes were present in this valley which have become converted into 

 swamps by the influx of material washed from the bluff. The meandering of the creek 

 over the bottom of Spy Run Lake basin forms the concluding topic. 

 ScovELL, J. T. Lake Maxmkuckee. Twenty-fifth Rept. Geol. Survey 



Indiana, pp. 233-47, 261-65, 1901. 



The features surrounding the lake and also the features of the lake bottom are 

 set forth by description and map. The flora of the lake is presented in a list of about 

 150 plants, not including 50 which are found along the beach. The lake contains a 

 large workable deposit of marl, which is thought to have had its origin through the sepa- 

 ration of calcic carbonate from the water by mollusks and different species of Chara. 

 An attempt made to form a rude estimate of the quantity of the carbonate of lime 

 deposited each year gave o.oi inch as a conservative amount. Assuming the average 

 thickness of the deposit to be ten feet, about 12,000 years would be necessary to pro- 

 vide for the accumulation of the marl. It is, however, thought probable that the rate 

 of deposition was more rapid in the past, so that the age of the lake may be consid- 

 erably less than 12,000 years. 

 SlEBENTHAL, C. E. Topography , Pleistocene Deposits and Drainage of the 



Hydraulic Limesto7ie Area in Southerti Indiana. Twenty-fifth Rept. 



Geol. Survey Indiana, pp. 359-64, 1901. 



Borings are thought to indicate that the Ohio River formerly passed the Louis- 

 ville rapids in a course slightly north of the present. 



ILLINOIS. 



Alden, William C. The Chicago Folio. Geol. Atlas of the United States, 



U. S. Geological Survey, Folio 81, 1902. 



This folio is very largely devoted to a discussion of Pleistocene features and 

 deposits, for the rock outcrops in the Chicago area are few, and it is the drift that 

 gives the topographic variations. The Valparaiso morainic system covers the western 

 edge; the remainder is largely embraced in the plain occupied by Lake Chicago. 

 The Chicago outlet, with its double-headed channel, forms a conspicuous feature in 

 its passage through the moraine. The discussion of glacial deposits pertains mainly 

 to the Wisconsin drift, though reference is made to exposures of earlier drift, and to 

 the penetration of old drift in deep wells. The lake history is treated in considerable 

 detail, and the several stages of Lake Chicago are shown by maps. In explanation 

 of the lowering of the lake level from the upper to the second beach a suggestion of 

 Chamberlin's is presented that the outlet may have cut back through the Valparaiso 

 moraine by a stoping process until the barrier presented by the moraine was removed, 

 and then lowering would rapidly take place. The changes in the present shore near 

 the mouth of Chicago River which have occurred since 1821 are represented on a 

 small map. The influence of the beaches of Lake Chicago on the course of Calumet 

 River is also shown on a special map. 



