uraninites

Furthermore the uraninites occur at the bottom of basins, often near uncomformities, below uranium bearing rocks, where we would expect such hydrothermal deposits to be found.

Luskin vs. Science (and Scientific American) - The Panda's Thumb 2006

From these considerations it would seem that unless the atomic weight of lead in uraninites, etc., is 206, the former complexity and more accelerated decay of uranium are indicated in the data respecting the atomic weights of radium and lead [1].

The Birth-Time of the World and Other Scientific Essays John Joly 1895