The predominance of juveniles from one taxon is rarely found in faunal studies. However, the presence of seven juveniles in a sample of ten cryptocleidoid plesiosaurs from the Redwater Shale Member of the Sundance Formation of Natrona County, Wyoming may be such a paleocommunity. Juvenile characters are recognized by the lack of facets and ossification on the distal ends of the propodials and by cross-sections of the limbs. Juveniles have dense pachyosteosclerotic bone structures whereas adults have more spongy, osteoprotic bone. The dense bone of the juveniles suggests a difference in environmental preference between juvenile and adult plesiosaurs.