  The established by us possibility to consider circumgalactic clouds (CGCs) as
the remnants of the parent clouds in which globular clusters (GCs) have been
formed (Acharova & Sharina 2018) is based on a comparison of the following
facts. First, the metallicities of CGCs at redshifts $ z <1 $ and of GCs in our
and other galaxies show a bimodal distribution with a minimum near $\rm
[Mg/H]=-1$. Mean values and standard deviations of the Mg abundances in GCs and
CGCs with $\rm [Mg/H]<-1$ and $\rm [Mg/H]> -1$ coincide within the typical
error of measuring the elemental abundances in clouds: 0.3 dex (Acharova &
Sharina 2018). Second, a similar coincidence is observed for GCs and CGCs with
$\rm [X/H]<-1$ and $\rm [X/H]> -1$ at redshifts $ 2 <z <3 $, where $[X/H]$ is
the metallicity determined from the sum of several elemental abundances (Dias
et al. 2016, Rafelski et al. 2012, Wotta et al. 2019, Quiret et al. 2016).
Third, high-metallicity CGCs are observed starting from redshifts $\rm z\le
2.5$, i.e. approximately 11 Gyrs ago. At the same time globular clusters were
actively formed, and their supernovae were able to enrich the surrounding gas,
from which the high-metal component of the clouds was formed.
