This paper deals with mode in nonrotating horizontally stratified dusty atmosphere. We have studied dust gravity and acoustic modes in presence of a barometric equilibrium in an unmagnetized dusty plasma. All the dust grains are considered to have same and fixed negative (positive) charge on them. The electron and ions are considered to obey isothermal equations of state while the dust grain are following an adiabatic equation of state. This work can be considered as a generalization of single fluid treatment of gravity-acoustic modes. The analysis of dispersion relation suggests that the dust grains can introduce a new decay length of the perturbation. Therefore we find that the dispersion characteristics of single fluid treatment is strongly modified in the presence of charged dust grain. Finally we discussed importance of our results in the context of planetary and stellar environments. ©2000 American Institute of Physics.