Laramie fauna began with just co- glomerate formations, these of the Drivson series, the Bonaovtue etc. Then followed red shale deposition of great thickness into the island studded range whose waters when evaporating under the arid climate and whose salt content was increasing from the land rocks as well from the sea supply. After the mountains had been greatly reduced and the volcanoes filled in, the supply of detrital material became less and less, the waters only thickened by the calcium carbonate of lime. Then the gypsum was thrown down at intervals between the red shale deposition. Finally once open sea prevailed, orlite making conditions pre- vailed and we had the deposition of the Drivson crinoids and faunas. Finally at the top we get the thin-bedded limestone with the Martinea flora fauna.