218 PllOCEEDINGS OF THE AMERICAN ACADEMY 



Here are schists with lentils of magnesian limestoue of three thou- 

 sand metres, or about nine thousand ieet, in thickness, extending from 

 the top of the most westerly range of the Green Mountains to the 

 borders of Lake Champlain. "With the help of the rare fossils to be 

 found in them, I have for convenience established four divisions in 

 these beds, making an upward series as follows: — 



At the base the St. Albans Group, three thousand feet thick, in which 

 only one or two fossils of uncertain determination have yet been found, 

 because the specimens have been lost or imperfectly studied. Tl.e 

 one found near the town of St. Albans, and also at Franklin, may be 

 an Olencllus or a Paradoxides ; the other, found at Highgate Falls, 

 may be a Pyyidium of Buthym-us ; also a fragment of Cephalopoda ? oi* 

 Pteropoda ? Finally, Salterella pidchella was found in a fragment of 

 Dove limestone near St. Albans, but not in situ. 



2d. Georgia slates, or slates with Olenellns ; they are about three 

 hundred and ninety feet thick. Two small lenticular masses of blue 

 and gray limestone, containing numerous fossils, are found at Swanton. 

 At Parker's farm in Georgia a calcareous sandstone which contains 

 iron geodes is found just above the Olenellus beds. The fossils are 

 Olenellus Thompsoni, 01. Verinontana, Peltnra holopyga, Angelina 

 Hitchcocki, Dikelocephalus ? Marconi, Conoccjjhalites Teucer, OholcUa 

 cingidata, Orl/iisina orientalis a.ud fcsfinata, and Camerella antiquata. 



3d. Phillipshurgh or Point Levis Group. — Light black slates, contain- 

 ing now and then large lenticular masses of limestone. At Phillips- 

 burgh the lenticular masses of limestone are ver}' numerous and closely 

 packed together, with only a sort of network of slates enclosing them, 

 and forming, as it were, a frame or border. At Point Ldvis the lentic- 

 ular masses of limestone enclosed among the black slates are less 

 numerous than at Phillipsburgh, and show a folding just at the chapel 

 near the St. Joseph church. The thickness varies, but it cannot be 

 less than three thousand feet. Fossils are numerous in some places, 

 and at some special spots more or less limited. These are what Bar- 

 rande has called Colonies of the second fauna enclosed in the strata 

 of the primordial faima, and I have named them precursory centres 

 of creation, or centres in which forerunning species or generic types 

 appear, that obtain their full development only during- the following 

 great period of the second fauna. 



The fossils belong to the following genera and species: Olenus? 

 Logani ; Dikelocephalus magnificus, Dih. planifrons, Dih megalops, 

 DiL Missisquoi ; Conocephalites Zenheri ; Mcnocephaliis Sedgwicki, 

 Men. Sulteri ; Bathyurus Saffordi, Bat. Cordai, Bat. bitubercidatus, 



