While rock between two consistent strata might in one place be shale and in another sandstone, the fossils in that shale or sandstone were always the same.
Between 1990 and 1998, road haulage increased by 19.4%, while during the same period rail haulage decreased by 43.5%.
在1990年到1998年间，公路运输增加了19.4%，而同期铁路货运量下降了43.5%。
3
While previously the gap between the continents had allowed a free flow of water, now the isthmus presented a barrier that divided the Atlantic Ocean from the Pacific Ocean.