I used cassandra and cassandra-all version 1.6.1 declares both log4j and slf4j-log4j12 as compile-time dependencies so I add following dependencies and my topology work like charm !!!
<dependencies>
<dependency>
<groupId> org.apache.cassandra</groupId>
<artifactId>cassandra-all</artifactId>
<version>1.1.6</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
<exclusion>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>