ci-oLdcY (IF M.\.\/i.\rr.\.\ 103 



lH)tli kinds arc louiul tojictlicr. Invcrtchratc lite, too, a|)|M'iir('(l on the 

 ^lol)e far earlier than vcrtchratc. and remains of certain sjx'cics arc al)un- 

 dant in the lowest (oldest) of our stratified rocks. 



The s])(H*iniens in the cases arc arranged to illustrate historical 

 jiieolojiv. hetriiHiiiio; at the nortlicast corner of tlic hall with the arcluean 

 Series rocks, which are the lowest and okh^st of all and contain no 



Illustrating fossils, advancinji; rej»;ularly southward alon^ the east side 

 Historical throup;h the ('anihrian, Ordovician, Silurian and Devonian 



Geology systems, passing to the west side of the hall in the 



Devonian and continuing; through the Carboniferous, Jurassic, Triassic, 

 Cretaceous and Tertiary. Thus far the specimens are from American 

 localities, but the northwest quarter of the hall is devoted to a synoptic 

 series of European fossils. The cases in the middle of the hall contain 

 overflow material from the sides. The American series is subdivided into 

 geographical provinces, the fossils from New York State and other 

 eastern regions being placed first and then the material from the Central 

 West and beyond. Under the geographical subdivision the species are 

 arranged according to their position in the scale of life — that is, following 

 a biological classification, the lower or simpler forms being placed first. 

 The diamond-shaped Ijits of emerald green paper attached to some of the 

 specimens indicate those, more than 8,000 in number, known as ''types" 

 or ''figured specimens," used by James Hall, R. P. Whitfield and 

 others in the original description and naming of species or in their 

 elucidation. 



The upper shelves and ends of the wall cases contain particularly 

 large or striking specimens of fossils, or blocks of rock illustrating the 

 geological features of the horizons in which the fossils occur. 



Two floor cases in the middle of the hall at the north end contain a 



series of rock specimens showing the geology of Manhattan 



Geology of Island and a very complete collection of the minerals found 



, in Xew York City and immediate vicinity belonging to the 



New York ]\Iineralogical Club. 



Attention may be called also to the collection of Michigan copper ores, 

 orbicular granites and diorites from several parts of the world, fossil 

 crinoids from Waldron and Crawfordsville, Indiana, fossil corals from the 

 Devonian reefs near Louisville, Kentucky, fossil crinoids and an immense 

 clamhke shell from the Cretaceous of Nebraska, fossil plants from 

 Tertiary beds at Florissant, Colorado. The windows contain some 

 colored transparencies from photographs of interesting scenery in the 

 West. 



[Return to the Hall of Mastodons and Mammoths and turning to the 

 right enter the West Corridor or Gem Hall.] 



