NO. 17 



SM nil SON I AX i-:.\ i'i.( ika riox.- 



KjK) 



21 



this particular shale. Liincstoncs known to he niiieh older outero]) 

 so short a distance to the east of this that a L^reat I'aidt or displace- 

 nienl hetvveen the two kinds of rocks is clearly indicated. 



With these facts in hand, the fault was traced for a diNtance of 

 thirty miles north and south, thus a,L;ain showing that the ^raplolites 

 ])rove(l the ke\- to the ^eolo.nic structure of the region. 



Ku;. 25. — l'"old in Ordovician shale west of VVilliamsi)()rt, .\1<1. (IraiJtolite 

 fauna found at A', where cleavage and bedding planes coincide. Fhottjgrapii 

 hy Rassler. 



i<:.\i'L()R.\'i"i()Ns IN liii-: OHIO v.m,li-:y for I'Ossil .m.c.M': 



AND CORAL RICEFS 

 Throuinh the extensive studies (jf the Secretary for several years 

 past, the collections of the National Museum are rich in liniestone- 

 f(jrniin,L; ])re-C"anil)rian ali;;e — a low order of water ])lants that secrete 

 lime or silica. An instructive series of these fossils has heen placed on 

 exhihition, hut in order to show the j^eolo^ic occurrence and evolu- 

 tion of this i^roup of ])lants it was necessary to supplement /he pre- 

 Camhrian forms with specimens oi more recent a.i^e. Accordingly 



