From two different samples: Vallée de Chaudefour (Auvergne) and a fountain at the bottom of the Sancy (volcanic mount), taken at two different magnifications, I wonder if they are the same diatoms.

(panorama of 8 images taken @ 20x - biggest size HERE)

(panorama of 6 picts takens @ 40x - most important size HERE)
Do you have any idea on the name of the diatoms ?
(genus ?)
Thanks