. BUFFALO SOCIETY OF NATURAL SCIENCES 141 



rare condition of the fossils. After tens of millions of years the exo- 

 skeletons of these organisms now so long extinct appear in the rock, 

 differing not in appearance from the shed skin of a Limulus buried in 

 the sand today. We must be filled with awe and with the profoundest 

 admiration for the marvellous ways of nature, when we look upon 

 these remains unchanged in chemical or physical characters during 

 all the aeons which have passed since they were entombed, still retain- 

 ing the brown color so familiar in modern horseshoe crabs, with the 

 very chitin of the test unimpaired, while even the brittle exoskeleton 

 itself, at times, can be removed from the rock intact. 



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Fig. 13. Sketch Map of Oesel for Upper Siluric Localities - 



History of Discoveries. This fauna was discovered in 1852 

 by Dr. Alexander Schrenk, during a trip made for the purpose of 

 studying the Ordovicic and Siluric rocks of the northwest provinces 

 of Russia, namely, Livland and Estland, and of the adjoining islands 

 Oesel, Dago, Moon, Worms, etc. On the first and largest of these 

 islands he found outcrops of the uppermost Siluric rocks in the town 

 of Rootzikull (see map, fig. 13) and there he came upon the first of 



