Dataset: mussels1.dat Source: J.J. Sepkoski, Jr., M.A. Rex (1974). "Distribution of Freshwater Mussels: Coastal Rivers as Biogeographic Islands," Systematic Zoology, Vol. 23, #2, pp. 165-188. Description: Numbers of species of mussels in 41 rivers, and independent variables: Area, number of stepping stones (intermediate rivers) to 4 major species-source river systems (Alabama-Coosa (AC), Apalachicola (AP), St. Lawrence (SL), and Savannah (SV)), Nitrate Concentration, Hydronium concentration (10^(-pH)), solid residue. Variables/Columns River 1-28 # species 31-33 Area (sq. mi.) 35-41 Stepping stones to AC 48-49 Stepping stones to AP 55-57 Stepping stones to SV 64-65 Stepping stones to SL 71-73 Nitrate 77-81 Solid Residue 86-89 Hydronium 92-97 ln(Area) 99-105