584 THE POPULAR SCIENCE MONTHLY 



ful profusion of the ancient life and help us to appreciate the wealth 

 of material that the paleontologist has at his command. In the quarries 

 at Independence, Iowa, there are beds crowded with beautifully pre- 

 served forms, mostly brachiopods, as perfect to-day in every detail of 

 shell structure and ornamentation as when the currents of life pul- 

 sated within. A coral reef, no species lost, has been cut into by a small 

 intermittent stream near Littleton, Iowa; and perfect coralla, wagon 

 loads of them, are strewn along the sandy channel a quarter of a mile 

 or more. A successor to the reef just noted, composed of different 

 species, the corals still in place, may be seen and studied on the west 

 side of the river opposite the village of Littleton. The state quarry 

 beds near North Liberty are simply cemented masses of brachiopods; 

 they illustrate the remarkable prodigality of the Devonian life, but the 

 individuals are not in good condition for study. It is a different case 

 that is presented by the fossils in the marly beds of the Lime Creek 

 shales at the exposures between Mason City and Eockford. A very 

 large proportion of the specimens here are as perfect as when the 

 animals lived; and there is a beauty and delicacy and exquisite refine- 

 ment about most of them that is scarcely matched, certainly not sur- 

 passed, anywhere among fossils of any age or time. More than 65 

 species occur in the Lime Creek fauna, and thousands of individuals 

 of some of the species, illustrating wide ranges of variation, enrich the 

 museums of the world. 



Along the Aux Sables Eiver at many points near Thedford and 

 Arkona, Ontario, there are calcareous shales containing a marine fauna, 

 or rather a succession of faunas which once flourished in wonderful 

 profusion and is still preserved in equally wonderful perfection. Sta- 

 tistics and computations would fail to give an adequate conception 

 of the abundance and character of the material here offered for study. 

 No detail of the skeletal parts has been lost; and as for the number of 

 individuals, they are simply uncountable. There lies before me a 

 small fragment of this old sediment having a surface of less than 15 

 square inches and it shows 51 identifiable individual specimens, not 

 counting stem segments of crinoids. The 51 individuals are distrib- 

 uted among eleven species, and these represent eleven genera — namely, 

 Phacops, Platyceras, Tentaculites, Spirifer, Chonetcs, Hederella, 

 Ortliopora, Clioetetes, Arthracantlia, Striatopora and Aulopora. Can 

 any bit of modern sea bottom of similar size make a better showing? 

 Above and below the Rocky Glen, near Arkona, from which this speci- 

 men came, there are opportunities to study continuous sections ap- 

 proximately 100 feet in thickness, the successive beds crowded with 

 organic remains and revealing the historic sequence of varying organic 

 types as the life responded to slight changes of environment. Here, 

 as at countless other localities, the paleontologist gets a view of 



