It is hard to understand why Alolan Golem are so fond of firing Alolan Geodude into the air, for using one's own young as a weapon seems at best an unlikely path to Darwinian fitness. There is probably no longer any benefit, only instinct, in this era when they live outdoors. Yet the ruins beneath Blush Mountain are as labyrinthine as Mount Moon, and archaeologists are broadly in agreement that Alolan Golem colonized every inch of it, and that their unusual means of doing so led to the cave complex's ultimate destruction.
Geodude around the world have always flocked to caves and high concentrations of this pokemon have troubled many a spelunker or pokemon trainer elsewhere; the difficult stratigraphy of the site suggests that Blush Mountain was no exception. What was unusual was that their Golem parents, powered by electricity, developed a weapon which Golem elsewhere lacked. When faced with overpopulation, they would use this weapon to blast their young through the walls, in the hopes of finding them a new, empty chamber to call home.
This behavior must have succeeded for quite some time in giving young Geodude new homes, for even today Alolan Golem will load their railguns with live Geodude if possible, and use the rocks so often depicted in scientific manuals only when no Geodude can be found. But the walls which supported the caverns were blasted apart faster than rock pokemon (including, at times, the same Golem who were shattering them) could build new ones, and in time the entire structure collapsed, leaving Golem rarer in Alola than anywhere else within their global range.
But the few survivors of that tragedy adapted well to the above-ground world, for they supplied and inspired the cannons that built an empire from Ula'ula Island and defended Alola's independence!