POST-GLACIAL MOLLUSCA 
661 
The fauna from these marls also indicates a cooler climate when 
the pond was occupied by the living mollusks, the southern limit 
of distribution of several of the species now being at a considerable 
distance north of this locality. Other extinct forms in this deposit 
were previously known only from the marls of Maine and Michigan. 
The distribution and other relations of the species from the Urbana 
deposits are shown in Table I; «x indicates that no authentic 
Illinois records are known. 
TABLE I 
MOoLiuscaNn DISTRIBUTION 
s Now Living Nearest Distance Bosal Known from 
Molluscan Species in Urbana or Illinois from Urbana Only Marl of 
Vicinity Locality in Miles Michigan 
Sphaerium rhomboideum.|.......... Menard Co. SOM ese ee AA ANA Eos ae ete 
Sphaerium occidentale...|.......... Fulton Co. . OGuiaadh taeem eee iy 
Musculium rosaceum....|.......... COURT alloc: girs | aalleneoue RE R M A Wet Hal aN as ahs ae 
Musculium truncatum.. . ee Siry  Uanlel rariNcayc ese aclu ec ee Le i IO 2 
Pisidium adamsi affine...).......... Winnebago 
ORF apa TiO eepvi ll eae eet x 
Pisidium contortum.....].......... oC Bee Ty if ep a pac aed Did Nea Se # 
IPisiaiumycostatumle eee tee ee eee SOKO NMI BUS Rin Mee - ~ 
Pisidium tenuissimum cal- 
CANCUMIN Ne re Uy eee ate em Lise 20 nena ete eet tegen * - 
Bisiciunm varialloil eke ese Mason Co.. CIS RUN Gees ae : 
Pisidium vesiculare......].......... ene ein eae ae yy a | zea aa 
Walvataicinceramante alee tee OG ce an Alb oes Mestre aren Pian OS lg A 
Walvatakitnicarina tales neti Mason Co. . CoVoyi Sealy a ene bi 
iRhysareyninag eee CC ALIAG GR PEA AE Ss a tka a Ua aA * 
Bhi salisaiyalbers tet akan a eu scok Peoria Co. SiMe Ny seve cae) Pere eae 
Planorbis trivolvis...... rau aban is] y Maen aT ott Ys Syne pac AMER aR = 
Planorbis parvus urban- 
TUS Sp reporter ate eae pes eo un Re teem Ja at LGN ease aap ONC BAHL 8 eh AEN Sh el aeeana AN tice PO 
kimonos AkneswianS.. 5 ally ooo ewe clas a oose ocd ollews 6 weiss yee | Waueraeee pata ned 
Galba caperata......... oT eg ela se KS cg gl Ka - 
Galba obrussa decampi..|.......... Wake; Con: AY Mey creel eens a aie = 
Gallbavretlexar: Mawnan Cia McLean Co. ASH Wray ace cots: ss 
An analysis of this table brings out several interesting features, 
as noted below: 
Species NOWsiving: inisameterdtonyen. rs. Nees o).. 
Species now, living imesamesatitudess ye. ee ee ite) 
Species not now living in state (not yet reported) 
TEXCIN CIS DECIES Ny manta meme nn Rak mino een wiie ate Aah e St 
Percentage of species also known from marl beds of 
Michiganvivne auepei mmr niatnmyen tur cep, nana Myth cf 
Percentage of marl fauna now living in Illinois... .. 
Percentage of marl fauna now living in vicinity of 
Urbana 
75 per cent 
70 per cent 
20 per cent 
