The paper is based on material obtained from 12 localities in Park, Chaffee, Eagle, Pitkin and Costilla counties, in Central Colorado.
The algal deposits include nodular masses, small “biscuits,” pisolitic limestones, compact, irregularly bedded limestones, and rounded colonies. Fourteen types were recognized, ten of which are new. They were named and described on the basis of form genera and form species.
Each form species may have represented several biologic species which lived in constant close association. They were probably deposited mainly by blue-green algae assisted by some green algae in the relatively shallow water of seas and lagoons.
The present work shows that some of the form genera had a wide geographic range and persisted through definite portions of the Pennsylvanian period. It also shows the important work of these lowly plants as limestone builders during the Pennsylvanian.