Wild Wacky Roof Gizmos

I'm on a continuing quest to get my landlord to make repairs around the house. Even better would be if I could get her to make repairs with some degree of sensitivity to the fact that the house is located in a historic district.

The house includes these wierd-looking tile things on the roof:

Several of the tiles were broken recently. Gary, my landlord's favorite cut-rate jack-of-all-trades handyman, took one look and observed "well, you can't get them things at Home Depot." He had a go at the broken pieces with liquid nails, but I have little faith that this fix is going to last very long.

So I'm on a quest to find out where, if anywhere, you can still get things like this. So far my Google searches for "roof thingies" haven't been successful. Anyone have any ideas?