diff --git a/c_tools/mock/generateFromCatalog.cpp b/c_tools/mock/generateFromCatalog.cpp
index badfa9c..5ae357b 100644
--- a/c_tools/mock/generateFromCatalog.cpp
+++ b/c_tools/mock/generateFromCatalog.cpp
@@ -589,7 +589,7 @@ int main(int argc, char **argv)
   cout << "Placing galaxies..." << endl;
   generateGalaxiesInCube(data, output_data, args_info.useComoving_flag);
   generateSurfaceMask(args_info, mask, pixel_list, full_mask_list,
-                      data, output_data, args_info.omegaM);
+                      data, output_data, args_info.omegaM_arg);
   
   saveForZobov(output_data, args_info.output_arg, args_info.params_arg);
   //  saveData(output_data);