Subsequent erosion stripped the granite of the overlying sediments and the softer adjacent schist. The reticular region is usually much thicker than the overlying papillary dermis. BMP4 stimulates differentiation of overlying ectodermal tissue. Typically this will involve a cover of sandstone overlying limestone strata undergoing solution. Odontocetes possess teeth with cementum cells overlying dentine cells. The vitreous humour is in contact with the vitreous membrane overlying the retina. Hydrothermal vents are locations on the seafloor where hydrothermal fluids mix into the overlying ocean. This goaf collapses under the weight of the overlying strata. These have a series of sedimentary units overlying them. BMP is initially secreted from the overlying ectoderm. The lithostatic pressure in the rock increases due to the weight of the overlying sediment. The lower five metres of the Qomolangma Formation overlying this detachment are very highly deformed. The image obtained includes the blood vessels, together with all overlying and underlying structures. Mapping of variation over an area is valuable in detecting structures obscured by overlying material. Nodes commonly become inflamed, thinning and fixation of the overlying skin.