242 Notes on Fresliicater Molhisca. 



This shell has been labeled Strophomena suhtenta, Conrad (>S. plicafa, 

 James); but it is clearly distinct froin that species, the only resem- 

 blance being the plications on. the cardinal line, and they differ 

 materially, being much less in number, in suhtenta, more oblique, and 

 less distinct; shading off in different individuals to almost nothing. 

 The internal markings are very different. 



Professor Billings, in his work on the " Palaeozoic Fossils of Canada" 

 (p. 130), has a shell, described and figured, strongly resembling our 

 species, and referred to S. suhtenta, Conrad, which (for the reason 

 given) it does not appear to be. 



Position and locality — upper part of Cincinnati Group, in Ohio and 

 Indiana. Collected by U. P. James. 



Notes on Fre&Inoater Mollusca, found in tJie vicinity of Chicago, Illinois. 



By W. W. Calkins. 



The writer lias pretty thoroughly worked up the species inhabiting 

 waters contiguous to Lake Michigaiii, and connected with it. A large 

 part of the shore, for many miles south and east of Chicago, is low and 

 marshy. At no distant day the lake extended mueh farther inland 

 than it does now. But having receded, the waters left a low coast and 

 immense swamps, bayous, and small streams, which cover thousands 

 of' acres. The Calumet Swamps formerly had their northern limit 

 about eight miles from the Chicago river. But the .rapid growth 

 of the city, and the speculation in real estate has now re- 

 deemed a large portion of what were a few years 'ago ' barren, 

 watery wastes, as far as South Chicago, at the mouth of the 

 Big Calumet river. Immense ditches, affording effective drainage, 

 traverse the country in every direction, so that land valued only 

 a few years since at not over ten cents an acre, is now selling 

 for as many hundreds. In the same bogs, where, four years ago, 

 ]iaught was heard but the croak of the frog and the scream of water 

 fowl, may now be seen the surveyor's stakes, and placards advertising 

 to the passer-by the advantage of buying a few s^vamp lots. Here I 

 have often collected hundreds of molluscs. Now, the dry earth and 

 peat deposits are filled with the dead shells. In the pursuit of 

 my favorite science, I am now obliged to travel from twelve to fifteen 

 miles. Calumet, Hyde, and Wolf Lakes, and the Calumet river, are 

 the mosi accessible points for the collector, and South Chicago a good 



