288 PRIMORDIAL FAUNA AND POINT LEV! FOSSILS. 
value, except so far as their relations to established genera may aid in 
that direction. 
The genera Dikellocephalus and Menocephalus are of the Potsdam 
group ; and so far, the Quebec group is in parallelism with the Pots- 
dam and Calciferous strata. 
Of the other genera, we know Asaphus, Illenus, and Ceraurus 
(= Cheirurus) in the Trenton limestone and Hudson River groups ; 
Illeenus and Ceraurus, Niagara age, or the third fauna of Barrande ; 
while Ceraurus occurs also in the Devonian of Europe. Amphion is 
known in the second fauna in Europe, and doubtfully in the first. 
Ceraurus does not occur in this country, so far as I know, above 
the Niagara group; though known in the Devonian rocks of Europe. 
The following tabular arrangement of the genera found in the 
Quebec group will serve to express more distinctly the relations of the 
Crustacean fauna of these rocks. 
The letters at the head of the columns have the same reference as 
those used in the communicalion of Sir William Logan. 
AC AE Ae u| A'S | AS) i 
Arionellus, .....-02+--eseceeseeeeee lice men TAA ciel ts osel atetell eee) ete 
Gonocephalus, ........02 0s cece eee nlenee me NPL. VHS acl ott oti etediefeis) etl» exsleyl alias 
AQMOStUS, = 2-220. eee eee eee ee ome Pa ey aa iiiagasilogsalleésos|looo> 
Dikellocephalus, ....--.--e++-ees-saleee SSG essallossaljases Bee 6 oe 
Menocephalus, ............+.-..+05- — | 1) —] — | — ]-- Jem lee 
IATA, sop soebdoboopoMooeoduOnloo oS —|4)4 Be crocs oll tates 1 
Barrandia, / Shales of Pics lotic alla o balla o dallas 2c 
Bathynotus, f Georgia, Vermont.|....|....)..--|eo--|sr-slers=|e2>s/oeee 
Amphion, ....-. 2 see cece eee cere eee fee cele nes ale Jaei[ ed! tisveveyethetevate | =ten=tsd| elslatte 
INSOIUS Cer aleietaleletelcle\e alala'elmiciiel~ aivicle amibatale 4 DUE See Ue reaialtees Sik 1 
aay idea Ser de Po Sees aa OHeor enon loeuale melehaciepalcosiiges ssc 2 
Cheirurus (Ceraurus),.......+..-.++-]....].... Je sialic 2) There oiea| eneenat teed eee 
Peperditia,(/ i. sf ere ale ws ale ela ll, we diaiulelailidls am [elec [ine a olmimials 1 
Lingula, .......- ee eeee sere eee eeee Z| — J] DQ Jrwcefeweclecscfecselecee 
DISCUS ale te lai le Ge (a ee oem m wleln)ele\njni]| ulnjaie see ae Ban ee Eo ilod olla oo. 
Gini ORS PORTE, Bie jie peat af tayo et) | ae 
Leptaena, .- 2. cece eee eee ee eee eee ee lenee —/|1 IRomoap oi lossaicss - 
Strophodonta, ......./..-eseeeeee selene At —icooalelaSiatolobe alias alinccs 
Glarere Wa cles eatretcietets srerstonsters tara liters Petar 1 il 13) oH ea ee 
Cyrtodonta? ............. IsbdonbooUloooaloSHalesoe (Uhloeol Onto les cia sac 
WECRUIREE) ad tgopospbouoeoUnboUOOOOOldbballdgus|docoloocctnooplladaalioooc 1 
Ming neonbe,” GHoscbbdaovedcoooEoposilsoacisoulloodc Balleshrlabcallocce 1 
MM ONIEN Hoooadooddokosoadeosiooocldeaciooge Mobilis ie'stadiars Wal sees 2 
EGGenoiN boo odoodongModuobabbopolldaddlace sec oe Aiviltais wrallialaierel| euorels 1 
ipa pPALOLVOS Melee 'n e sje'o's wl esse «vise aleilcrererol| (stale ailiste ele Mer ltateraretiierata rel erorekal| ketal 
OR gneR S45 Ubud aMaseemmasosoqusiionso ith asia DIE isvetcfelli sie stoi] ais eta feletats 
Ophileta,.....0. 200... eee cece eet e wate ee elecee [en ne[eseeteesctecseleres 1 
ET NGH ap odes onoGosoGa vonodaodou|logseioumelionacibdcnilidcaioodaloor 1 
@ELHOCET AS fe\ay= alele\n's/e'e'n\inje)c\eln co n/a) slates ata WiciWiell ataletd atts oilile wist fata i'l ler ste 3or4 
