back of the bridge over the brook one sees the contact with the asphyxolite. The basal material appears to be either rolled down asphyxolite clay with quartz pebbles or it is the rounded soil and then a fine grains conglomerate, in any event the asphyxolite was weathered and was land on which the Silurian sea migrated. As all rotns brook are of the Beccary this formation is hard and sandy and makes cliff. The bridge stands on the uppermost beds of it and to the north the land at once descends into the lower ground of the Roro Brook dale. Billions give the thickness as 200 feet.