230 
The Aiucrica)i Geologist. 
October, 1901. 
It is quite certain from the results of the Challenger ex- 
pedition that the hothymetrical range of bivalves is most var- 
iable, as this compilation shows. 
Genera 
Depth in 
Fathoms 
49 
1400 
Martesia 
Teredo 
Gastrochaena 8 
Clavagella 7 
Solecutus 28 
Saxicava 100-500 
Mya 7 
Corbula 7-435 
Anatiua 18-28 
Periploiua 13 
Lyonsia 620-1950 
Silenia 1950-2650 
Thracia 20100 
Neaera 120-1950 
155 
Genera 
Poromya 
Pandora 7 
Myodora 6-17 
Myochama 6 
Mactra G-20 
Raeta 7 
Psammobia 6-70 
Tellina 6-155 
Donax 10 
Semele 7-1000 
Ervilia 6-1000 
Davila 20-150 
Veiius 3-1000 
Tapes 6-50 
Cytherea 7-70 
Circe 2-435 
Dosinia 6-25 
Venerupis 70 
Petricola 8 
Cardium 10-70 
CalloQardia 1000-2900 
Chama 7-450 
Lucina 7-435 
Tridacna 8 
Cryptodon 5-1900 
Diplodonta 6-150 
Kellia 2838 
Montacuta b-ioO 
Solemya '^"^'^ 
If the Devonian lamellibranchs were expelled by the phys- 
ical constants pertaining to the Marcellus and the Genessee or 
Portage, the expulsion of the Ammonoid fauna of the latter by 
the physical constants of the Hamilton and Chemung also ex- 
cites comment. The Naples fauna, described by Dr. Clarke, 
is essentially cephalopdous. the Marcellus calcareous shales 
also contain a goniatitic fauna. There is an essential sim- 
Depth in 
Fathoms 
Astarte 70-100 
Crassatella 28-390 
Cardita 10-60 
Carditella 20-100 
MytiluB 6-350 
Myrina 1400 
Crenella 140 
Idas 390 
Modiolaria 2-1675 
Modiola 15-800 
Perna 10 
Lithodouius 8 
Dacrydiuni 100-390 
Modiolarca 12-245 
Septifer 12 
Julia 40 
Avicula 8-30 
Malleus 3-12 
Pinna 38 
Area 12-2000 
Trigonia 2-38 
Glomus 390-1900 
Pectunculus 7-1010 
Limopsis 28-1850 
Nucula 10-2050 
Nuculina 1-^-20 
Leda 12-1675 
Sarepta 2385 
Yoldia 28-345 
Malletia 60-2550 
Pecten 2-1375 
Lima 2-2500 
Amussium 20-1675 
Spondvlus 8-28 
Plicatula 15-21 
Anoraia 50-350 
Ostrea 28 
