PLATE 2 

 AQUATIC GASTROPODS AND SPHAERIID FRESH-WATER MUSSELS 

 Various magnifications 



Figs. A, B, C. - Gyraulus parvus (Say); spiral, apertural, and umbilical views, 

 respectively. Basal zone of Peoria loess, SE| SW| sec. 26, T. 4 N., R. 

 3 E., Fulton County. Enlarged approximately 5X. 



Figs. D, E, F. - Valvata trlcarinata{Say); spiral, apertural, and umbilical views, 

 respectively. Farmdalian water-laid silts, Wedron Quarry section, SE| 

 SE| SW{ sec. 9, T. 34 N., R. 4 E., La Salle County. Enlarged approxi- 

 mately 3^X. 



Figs. G, H, I. - Gyraulus altissimus Baker; spiral, apertural, and umbilical views, 

 respectively. Farmdalian water-laid silts, Wedron Quarry section, SE| SE{ 

 SW{ sec. 9, T. 34 N., R. 4 E., La Salle County. Enlarged approximately 

 5X. 



Figs. J, K, L. - Valvata slncera Say; spiral, apertural, and umbilical views, re- 

 spectively. Farmdalian water-laid silts. Lake Bloomington Spillway sec- 

 tion, SW{ NE{ sec. 1, T. 25 N., R. 2 E., McLean County. Enlarged ap- 

 proximately 4X. 



Figs. M, N, O. - Planorbula armigera (Say); spiral, apertural, and umbilical views, 

 respectively. Basal zone Peoria loess, SE^ SW{ sec. 26, T. 4 N., R. 3 E., 

 Fulton County. Enlarged approximately 4X. 



Fig. P. - Amnicola leightoni Baker; apertural view. Farmdalian water-laid silts, 

 Wedron Quarry section, SE| SE| SW} sec. 9, T. 34 N., R. 4 E., La Salle 

 County. Enlarged approximately 4X. 



Fig. Q. -Amnicola lustrlcn (Say); apertural view. Farmdalian water-laid silts, 

 Wedron Quarry section, SE{ SE| SW{ sec. 9, T. 34 N., R. 4 E., La Salle 

 County. Enlarged approximately 4X. 



Fig. R. - Aplexa hypnorum (Linne); apertural view of incomplete specimen. Basal 

 zone Peoria loess, SE{ SW{ sec. 26, T. 4 N., R. 3 E., Fulton County. 

 Enlarged approximately 2 1/3X. 



Fig. S. - Lymnaea parva (Say); apertural view. Sandy silt inclusion in Metamora 

 moraine, center NE{ sec. 25, T. 27 N., R. 4W., Woodford County. En- 

 larged approximately 3|X. 



Fig. T. - Lymnaea dalll Baker; apertural view. Basal zone Peoria loess, Enion 

 North section, SE| SE| SW| sec. 28, T. 4 N., R. 3 E., Fulton County. 

 Enlarged approximately 4X. 



Figs. U, V. - Pisidium nitidum (Mighels); internal and exterior views of right valve, 

 respectively. Farmdalian water-laid silts, Wedron Quarry section, SE| SE| 

 SWi sec. 9, T. 34 N., R. 4 E., La Salle County. Enlarged approximately 

 6X. 



Figs. W, X. - Pisidium obtusale Prime; interior and exterior views of right valve, 

 respectively. Farmdalian water-laid silts, Lake Bloomington Spillway 

 section, SW^- NE} sec. 1, T . 25 N . , R. 2 E . , McLean County. Enlarged 

 approximately 6X. 



Figs. Y, Z. - Pisidium compressum Prime; exterior and interior views of right valve, 

 respectively. Farmdalian water-laid silts, Wedron Quarry section, SE| 

 SE{ SW{ sec. 9, T. 34 N., R. 4 E., La Salle County. Enlarged approxi- 

 mately 7X. 



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