A series of glaciations further modified the region starting about 2 to 3 million years ago and ending sometime around 10000 bp .
约2至3百万年前开始并于距今约一万年前结束的一系列冰川进一步改造了这个地区。
He explained that one represents a lineage that was pushed south during the last glaciations and survived in what is now the united states .
他解释称其中一支是在上一次冰河时代被迫南迁至现在的美国并存活下来的。
Hmm. at the time our colleague suggested that maybe these were delta deposits or possibly glacial outwash ( although we don 't know the extent of past glaciations in the park ) .
