The Mt Difficulty satellite vineyards are also widely varying in their soil types: Keillor Vineyards comprises Lochar soils similar to Long Gully and Target Gully as well as Manuherikia soils. These are described as having more than 45 cm of silty or loamy relatively fertile top soil over terrace gravels. Desert Heart Estate consists of Lochar soils as well as the hilly phase of Lochar soils – differing from the standard Lochar soils only insofar as it consists of a higher proportion of gravels and less of the finer soils. Ferris Vineyards are the result of dune formation from parent material blown across the river from the Cromwell flats. They are very low in both fertility and water holding capacity. Drainage is, if anything, too good.