stable or falling water levels, and permit differen tiation between gradual and sudden transgression The level of Lake Ontario was long assumed to of the shoreline. Vegetational succession reflects have risen at an exponentially decreasing rate shoreline transgression and increasing water solely in response to differential isostatic rebound depth as upland species are replaced by emergent of the St. Lawrence outlet since the Admiralty aquatic marsh species. If transgression continues, Phase (or Early Lake Ontario) 11 500 years B. P. these are in turn replaced by floating and sub (Muller & Prest, 1985). Recent work indicates merged aquatic species, commonly found in water that the Holocene water level history of Lake to 4 m depth in Ontario lakes, below which there Ontario is more complex than the simple rebound is a sharp decline in species richness and biomass model suggests. Sutton et al. (1972) and (Crowder et al., 1977). This depth varies with Anderson & Lewis (1982, 1985) indicate that physical limnological conditions in each basin. periods of accelerated water level rise followed by Because aquatic pollen and plant macrofossils are temporary stabilization occurred around 5000 to locally deposited, an abundance of emergent 4000 B. P. The accelerated water level rise, called aquatic fossils reflects sedimentation in the littoral the 'Nipissing Flood', was attributed to the cap zone, the part of the basin shallow enough to ture of Upper Great Lakes drainage. support rooted vegetation."

stable or falling water levels, and permit differen tiation between gradual and sudden transgression The level of Lake Ontario was long assumed to of the shoreline. Vegetational succession reflects have risen at an exponentially decreasing rate shoreline transgression and increasing water solely in response to differential isostatic rebound depth as upland species are replaced by emergent of the St. Lawrence outlet since the Admiralty aquatic marsh species. If transgression continues, Phase (or Early Lake Ontario) 11 500 years B. P. these are in turn replaced by floating and sub (Muller & Prest, 1985). Recent work indicates merged aquatic species, commonly found in water that the Holocene water level history of Lake to 4 m depth in Ontario lakes, below which there Ontario is more complex than the simple rebound is a sharp decline in species richness and biomass model suggests. Sutton et al. (1972) and (Crowder et al., 1977). This depth varies with Anderson & Lewis (1982, 1985) indicate that physical limnological conditions in each basin. periods of accelerated water level rise followed by Because aquatic pollen and plant macrofossils are temporary stabilization occurred around 5000 to locally deposited, an abundance of emergent 4000 B. P. The accelerated water level rise, called aquatic fossils reflects sedimentation in the littoral the 'Nipissing Flood', was attributed to the cap zone, the part of the basin shallow enough to ture of Upper Great Lakes drainage. support rooted vegetation."

From the late 1930s to the mid-1950s, five big movie studios-Paramount, Warner Bros., Twentieth Century-Fox, Metro-Goldwyn-Mayer (MGM), and RKO-dominated Hollywood's film industry. This "big studio system" operated primarily as a series of assembly-line production factories. Ideally, each churned out fifty-two movies a year, enough to supply showcase theaters across the country with a new lineup each week-with profit being the overriding goal.

Of this era, veteran screenwriter Julius Epstein ("Casablanca") said: "It was not called the motion picture industry for nothing. It] was like working at belts in a factory."

Studios assigned the majority of the lower-tier screenplays to directors under long-term contract and expected them to stick to the script and keep productions within the budget. These filmmakers, known as "house directors," often made films quickly, inexpensively, and with limited resources. "Just Making Movies: Company Directors on the Studio System" collects twelve interviews with house directors from this era, all conducted by the author during the 1980s. These previously unpublished interviews provide a clear picture of how the big studio system operated, as told by those who knew it best.

Despite limitations, house directors sometimes made enduring film classics, such as Charles Walters's "Easter Parade," Henry Koster's "The Bishop's Wife," George Sidney's "The Three Musketeers," and Vincent Sherman's "The Hasty Heart." In these interviews the filmmakers talk candidly about working with such superstars as Joan Crawford, Errol Flynn, Richard Burton, Bette Davis, Judy Garland, Cary Grant, Esther Williams, and Lana Turner.

Ronald L. Davis is professor emeritus of history at Southern Methodist University. He is the author of "Van Johnson: MGM's Golden Boy" (University Press of Mississippi) and "The Glamour Factory: Inside Hollywood's Big Studio System."

The word is spreading among outdoor enthusiasts and nature lovers that bogs and fens (peatlands) are among the most fascinating and beautiful places to visit. This growing reputation, along with the development of boardwalks that allow a close look at the ecosystem without getting one's feet wet, has led to an upsurge in visits to these wetlands. To aid the increasing number of bog walkers, Ronald B. Davis has produced an attractive and informative guide to the trees, shrubs, and wildflowers of the peatlands of the greater American northeastern region. The book covers 155 of the species most likely to be discovered alongside the boardwalks and presents stunning photographs of 98 of them. It includes a primer on the ecology of peatlands and offers an invaluable guide to 78 peatlands with boardwalks across the region. This essential guide to the wonders of the bog trails will appeal to boardwalk newbies and old pros alike.