Mexico City Monday Sep. 10-1906. In the morning attended the session of the Congress. Some time was devoted to a discussion of geological climates. Ordnis was the first speaker as Chamberlin had to leave the city. He offered no particularly new views but indicated the old and new ideas of in- terpreting geologic climates. He thought the old idea of cooling earth had to be laid one side be- cause of the Cambrian glacial period, and especially because of the indication that there may have been Precambrian glacial periods. Last year he had seen the Dwyka conglomerate of S. Africa and it indicates that this Permo- Cretaceous glacial region had not been laid down in a high country but that the land here had totally been reduced to a low land. This region was not far south of equator. A cooling climate he did not think the probable explanation but due to some oscillatory cause. He suggests a cold climate with a summer snow fall. Beetle suggested that as Loengly had shown that the sun is a variable star may the glacial climates etc due primarily to this cause.