HISTORICAL SKETCH. xliii 
the upper layers of the buff limestones of the Trenton group,” or ‘‘ buff limestones near 
the middle of the Trenton group,” or ‘‘blue beds of the Trenton limestone below Carpenter’s 
quarry ” (at Beloit). Sometimes the description involves such combinations as ‘‘hard lay- 
ers of the bluish-buff limestones of the Trenton group, below Carpenter’s quarry,” and 
again ‘‘Lower Buff limestone of the Trenton group below Carpenter’s quarry,” or ‘‘in the 
Buff limestone of the Trenton group at Carpenter’s quarry.” This variety ef usage of 
the terms Buff and Blue is explainable by reference to the abstract already presented, of 
the report of Prof. Chamberlin in 1878. Prof. Whitfield describes and illustrates 36 
species from the Trenton, being: lamellibranchs, 6; gasteropods, 16: pteropods, 1; cephal- 
opods, 10; and crustaceans, 3. 
The following species are said to more particularly characterize the Galena limestone: 
Receptaculites oweni Hall, Halysites catenulatus, Fischer, (two specimens from Rockton, 
Tl.) Lingulella iowensis Owen, Hemipronites americanus Whitf., Murchisonia major Hall, 
Fusispira ventricosa Hall, Fusispira elongata Hall, Maclurea cuneata Whitf., and Mac- 
lurea subrotunda Whitf. 
The Hudson River species illustrated are, five species of Radiata (Chastetes, Alveolites 
and Monticulipora), eight species of Bryozoa, and ten of Brachiopoda. 
The general list of species given in this volume by Prof. Whitfield is enlarged and 
reproduced in volume 1, which was the last volume of the report to be published. It is 
condensed below, from vol. I. 
CLASS. 1 2 || H.R.| Gal. |Trent 
IERIGASNGID:Atraycteyeyctoterasoteieyeretavera ate ovcll eral ctalsoieietcierevevele(erestefeyotsvatctatsd tcraxevotane tele tetcye-ccelsterd otal ovetokatets 3 1 3 7 
ROTOZO Au Ee wlOs POU Gldicetietctafelatsievetereiateletelelelelaleielet elolelefalelareteictorer=aialeralevelieletelel| siete tere IP Mleodece 1 1 
INGRAM AITE Es cacodoLe dopode poeuaoedoEcdde Hod doa osao baer bosuandd|scoouallooooanl||\dc0tac Bia | aeons 
VATA PAO NIWA Mancoosaesasoncoood  GoobemocoEccUSdabbesoaU condone Foor [seco ual|addocol||sonadallssoodell coos 
PAL CY ON Arian (GLAP LOM) sarlelelevelelslelniacictels/ceievsrelelciaiseretcieialelere aievsisieiare 1 u 1 3 5 
ZOANUTAALIA—CA DURA area tcrelelele cistetere sleleteielcle ciate sisicler cists eistalnie/sferaisletaievetaraie 3 3 19 3 8 
Zoantharia—rugosa,............. duddoneepebodEeanuTdovanE conemene 1 3 1 4 5 
1) NDTUNT WAI HO VINO EIOITE YI) 05 no oASD Oo Dan oOnadbangUuDoxD ED Ltlndonasodsoe Doug |soK00d||ocoodollloonood||odcdu cel [aaodtse 
CY SULT eae eee eee real a oieTa toate ele arolene aleraie ete eialer rovers laleteserelals cLslerstel|lelekaieroie}| aleteteiore || ersictelese Ae | aerersie 
Grin Oldleary censeieraitetele eetetietelelaierereloleteiarelcis ol sfuleistetsieracinrais ersveteleielstetese ores 3 1 3 4 
MOU SCAL—MOMPSCOIO eae crlerceretoeieeislercielaleisiclerelateratcistalaissoiees oiernteiarcserevel | ctelarata/el| (svetetszeval||(arevarel te] lleretotefose)| serrate 
ISIN OVATE emSaode nh Ge na CS SuOHGODGOCnOHE DUG OFOaad Se coMcioT cooneCae dc 2 5 17 5 8 
IBrAChlOPO aiascwssc eae sina clleisioters Neisjecsre save rele glaiaisiaversins s/najelere.sereticielpis 12 23 30 29 43 
MOLT USCA —MONUSCA) PLOPED.. . n.0 cele cones view cle cece ce cee cleo nice ceje are oe|eieie sie) ||s\ecisie\e Ilene 2 10)|/s\o1eaiein\llr sie 3 
Lamellibranchiata.. 50 solloaace 4 2 4 24 
Gasteropoda....... as 1 12 3 19 28 
Heteropoda.... Hal idaacollooceDallledaacd 1 6 
Pteropoda ... 68 Badoos pacdo alaagues 1 3 
Gephalomoddncwitrecia cust earesteicle neice cie ol tole cieitiass aisistaieicrevel stelle wieie(eros aF-fers)| emer i | | esteververs 3 37 
ARIBIG WiTAC AN —AATI TION Glo ayeiererctciet ohatetetalctevateteretalet ever alersvelicreleyeileie ciclelcs e¥e)esera erekelo ciel] |scayaleieeell = =iel=) si | \sl(aloia\s\|farsislerers 1 
Crustacea:— 
Entomostraca ......... SCAU Lona Beso COTE nOOdoReD er onTore no sodd desuss al ieaoeee 2 
ELI Oiler ateperateretereteiets sdaonbudoccoodooddnaalbo odaeocooRo 2 4 3 8 17 
PICO GaESPOCLES: etarstatsr teyervetereierars ersten <iotaieceleVaieralsvele(als etote) tote’ ofa’ sie/ais 22 64 79 94 | 199 
Total species identified with the Lower Silurian, 278. 
CoLUMN 1.—Species common to the Hudson River and the Galena, 22. 
COLUMN 2.—Species common to the Galena and Trenton, 64. 
Note. In each of these comparisons we may note the closeness of affinity by the ratio 
of the common species to the smaller one of the faunas compared, and in this way we find, 
