These names allowed me to replace the old
using Microsoft.Practices.EnterpriseLibrary.Logging;
that we were using, with:
using Log4netWriter;
Then modify the Logger.Write() calls very slightly, and then was ready to log with log4net

namespace Log4netWriter
{
public static class Logger
{
static Logger()
{
XmlConfigurator.Configure();
}

public static void Write(string message, string category, TraceEventType logLevel)
{
ILog Logger = LogManager.GetLogger(category);

switch (logLevel)
{
case TraceEventType.Verbose:
Logger.Debug(message);
break;
case TraceEventType.Error:
Logger.Error(message);
break;
case TraceEventType.Critical:
Logger.Fatal(message);
break;
case TraceEventType.Information:
Logger.Info(message);
break;
case TraceEventType.Warning:
Logger.Warn(message);
break;
}
}
}
}