  The relationship between young stellar clusters and respective parental
molecular clouds is still an open issue: for instance, are the similarities
between substructures of clouds and clusters just a coincidence? Or would they
be the indication of a physical relationship? In order to address these issues,
we have studied the CMa OB1/R1 region that shows evidence for a complex star
formation history. We obtained molecular clouds mapping with the IRAM-30 metre
telescope to reveal the physical conditions of an unexplored side of the CMa
region aiming to compare the morphology of the clouds with the distribution of
the young stellar objects (YSOs). We also study the clouds kinematics searching
for gradients and jet signatures that could trace different star formation
scenarios. The YSOs were selected on the basis of astrometric data from Gaia
EDR3 that characterise the moving groups. The distance of 1099$_{-24}^{+25}$ pc
was obtained for the sample, based on the mean error-weighted parallax. Optical
and near-infrared photometry is used to verify the evolutionary status and
circumstellar characteristics of the YSOs. Among the selected candidates we
found 40 members associated with the cloud: 1 Class I, 11 Class II, and 28
Class III objects. Comparing the spatial distribution of the stellar population
with the cores revealed by the 13CO map, we verify that peaks of emission
coincide with the position of YSOs confirming the association of these objects
to their dense natal gas. Our observations support the large-scale scenario of
the CMa shell-like structure formed as a relic of successive supernova events.
