Show california coast ranges comparatively modern washington Cali fornias earth quake plagued coast ranges first started to grow only a short time tim before tho the ice ago began and received their most recent uplift only a few thousand years ago accor according d to data reported recently by dr W P woodring of the united states geological survey rising first during the pliocene period age of giant mammals lust just before the beginning of the ice ages to part of their present height tho the coast ranges were thrown int into 0 a jumble of ridges and basins somewhat resembling their present construction st ice age erosion during the time of alternating glacial periods and warm spells changed the shape of the original mountains somewhat removing material from the higher it was stated evidence has been presented during the past generation to prove that the coast ranges were built a any ny time from about years ago to years ago but the most recent studies lead to the conclusion that the greatest uplifting and de formation took place during the pleistocene period time of ice ages which probably began not more than years ago |