Whitlock lithium project, page-3

Here's a wider view. This shows why the earlier drilling was barren in terms of lithium, they were testing the Peterson Creek formation, not pegmatites.


Closer up to the area of interest:



The pegmatitic granites intrude into the felsic volcanics of the Bernic Lake formation and diorite of the Birse Lake pluton, which continues west to host Tanco's pegs under cover.

From: Geology and structure of the Bird River Belt, southeastern Manitoba (NTS 52L5 and 6)
by M. Duguet, H.P. Gilbert, M.T. Corkery and S. Lin, p. 170-183.