  We present the results of the study of the substructure and galaxy content of
ten rich clusters of galaxies in three different superclusters of the Sloan
Great Wall. We determine the substructure in clusters using the 'Mclust'
package from the 'R' statistical environment and analyse their galaxy content.
We analyse the distribution of the peculiar velocities of galaxies in clusters
and calculate the peculiar velocity of the first ranked galaxy. We show that
clusters in our sample have more than one component; in some clusters different
components also have different galaxy content. We find that in some clusters
with substructure the peculiar velocities of the first ranked galaxies are
large. All clusters in our sample host luminous red galaxies. They can be found
both in the central areas of clusters as well as in the outskirts, some of them
have large peculiar velocities. About 1/3 of red galaxies in clusters are
spirals. The scatter of colours of red ellipticals is in most clusters larger
than that of red spirals. The presence of substructure in rich clusters, signs
of possible mergers and infall, as well as the large peculiar velocities of the
first ranked galaxies suggest that the clusters in our sample are not yet
virialized. We present merger trees of dark matter haloes in an N-body
simulation to demonstrate the formation of present-day dark matter haloes via
multiple mergers during their evolution. In simulated dark matter haloes we
find a substructure similar to that in observed clusters.
