American Sign Language (ASL) is historically related to French Sign Language (FSL) of the early 19th century. A study underway at Gallaudet College is researching the historical development of both languages treating syntax, lexicon and formation. This paper deals with data in the form of still photos collected in France and published in a dictionary by Pierre Oleron. Comparison is made of formational differences between modern FSL and modern ASL signs. Differences are discussed in terms of fluidity in compounds and differences in locations, movements and handshapes. Some differences relate to historical change processes in ASL: variations in fluidity of compounds; centralization; elbow-to-hand shift; morphological preservation; compensatory lengthening; simplification of movement; assimilation of movement; rule of thumb; loss of handshape; assimilation of handshape, and G-to-H change. Other variations may be products of early creolization of FSL and ASL: movement metathesis; maximal differentiation of movement; metathesis of handshape and maximal differentiation of handshape. When there is a relation of historical change between signs of FSL and ASL, the FSL sign usually has an older form. Relationships between FSL and ASL are highly systematic and similar to historical relationships among oral languages. (CHK)