Make linked site plan visible in first floor plan

I have a Revit building model into which I have linked a site model with a toposurface.
In the building model, I can see the toposurface in the Site plan, but not in the first floor plan.
I would like to make the toposurface visible in the first floor plan, but haven't been able to do it by changing view depth to unlimited and changing the visiblity/graphics.
What am I missing? Thanks.

Make sure Topography is turned on in VG under Model Categories, and if it's a Linked model use Custom settings in VG under Revit Links to turn on topography.

Also, you might try using an Underlay in the first floor plan?

Thanks, Cliff, but I'm still not there.
V/G from the first floor plan, Topography is on in Model Categories, in Revit Links I click on Display Settings, change to Custom, click on Model Categories, change to Custom, verify that Topography is checked. But no change in the plan view, I still don't have the toposurface.
The site link is an overlay rather than attached - does that make a difference?
"Site" isn't listed as a option in Underlay for the first floor view.

Can you see it in wireframe view?

Also, just be be extra sure--make sure primary and secondary contours are checked under VG>Model Categories>Topography.

Also, under the ribbon, check Site Settings.

Cliff -
One problem solved and another created!
I had drawn the site plan model in Phase 1, but the first floor view was in Existing Phase. I changed the site model to Existing phase and reloaded it. I can see the toposurface now, but oddly (it seems to me) the toposurface is colored in some views (Site, Basement) but grey in others (First Floor). All views are set to the same Display Style (Shaded).
Thanks again for the gift of your time and knowledge. I feel like a bull in a china shop.

Sound like your "Phase Filter" is different, probably 'Show Complete" compared to "Show All" - Check your view properties

Regarding colours: if you have more than two phases then the objects drawn before the current phase are all coloured differently regardless of their material (with some Phase Filters).

In a Phase: Phase 2 view with Phase Filter: Show all
- Existing is shown as existing (with an override to Material: Phase - Exist
- Phase 1 is also shown as existing
- Phase 2 is shown as New Construction

So even if you have the same object (eg Topography/ Wall ...) with the same material in both Phase 1 and Phase 2 they will be shown differently.

This is often quite helpful but came as a surprise to me.