THE STORY OF OUR ROCK FOUNDATION 



53 



FIG. 36. Fossils from the Pennsylvania!! coal measures, Mazon Creek, 111. 

 All plants except e. a, Alelhopteris ambigua Lesqx.; b, Neuroptcris vermicularis 

 Lesqx.; c, a horsetail, Annularia stellata Schl.;' d, Sphenophyllum marginatum 

 Brougn.; e, a crustacean, Acanthotelson stimpsoni M. & W.; /, Palmatopteris fnrcata 

 Potonid.; g, bark of SigUlaria sillimani Brougn. Plant photos by P. O. Sedgwick. 



