36 TRANSACTIONS OF THE 
pearance with Limestone strata. Thus far no unconfor- 
mity has been found between this and the preceding strata. 
For a short period conditions were favorbable for sustain- 
ing the fauna that had migrated from the Northern Pacific 
south, in the Jurassic Sea, but these conditions were not . 
long lived. As I said before the evidence is that the south- 
ern end, at least, of this bay was disconnected and broken up 
into lagoons. Through concentration by evaporation the 
environment became unsuited for the maintenance of living 
organisms, and the meager fauna which had migrated so 
far from its origin died out during the first two hundred 
feet of strata of the Middle Jurassic series, never to appear 
again in this locality. . 
The fossils found in this two hundred feet are as 
follows: 
Pentacrinus asteriscus. 
Ostrea strigilecula. 
Camptonectes stygius. 
Camptonectes pertenuistriatus. 
Camptonectes platessa. 
Camptonectes platessiformis. 
Trigonia quadrangularis. 
Trigonia montanaensis. 
Trigonia sp. 
Pinna kingii. 
Tancredia inornata. 
Astarte packardi. 
Modiola subimbricata. 
Pholadomya kingii. 
Cyprena sp. 
Pseudomonotis (Eumicrotis) curta. 
Pleuromya subcompressa. 
Pleuromya sp. 
Gervillia montanaensis. 
Cyprinus sp. 
Lima (Plagiostoma) occidentalis. 
Liman. sp. 
Neritina phaseolaris. 
Cardioceras sp. 
Belemnites densus. 
Serpula sp. 
