Who is buried in Weierstrass' tomb?
Amazingly, if you dig down in the tomb of Weierstrass, you will find Euler! See
Euler, Institutiionum calculi integralis volumen primum, 1768, E342, Caput V, paragraph 261.
Go to http://www.eulerarchive.org/ and search for Index Number E342. There you will find the original Latin as well as an English translation by Ian Bruce.
This reference comes from Analysis by Its History by E. Hairer and G. Wanner (Springer 1991), p. 123. I have checked their reference and they are correct.