 This indicates that the Finlay tephras are Early Holocene in age and were deposited shortly after the regional Fraser Glaciation retreated.The Finlay tephras are largely composed of elements most similar to those of Hoodoo Mountain, a flat-topped volcano that formed subglacially at least 100,000 years ago.Two phonolitic lava flows on its south flank were erupted between 10,000 and 9,000 years ago and remain unglaciated.