求翻译：在龙岗山脉以西，河谷熔岩的下伏地层是陆壳基底(各期老地层)，山脉以东，河谷熔岩覆盖在小椅山期熔岩之上，具有明显的多期性，晚期熔岩流覆盖在早期熔岩流之上，在熔岩流前锋形成特征的阶梯状产状。是什么意思？

In Longgang Mountains west of the underlying strata of the valley lava continental basement (of the old strata) east of the mountains, valley lava cover the top of the mountain of lava in a small chair, with the obvious multistage late lava flows covering the top of the early lava flows, lava flows

Longgang mountains in west Valley, and lava formations of the Volt is currently base (the old ground, mountains, and East Valley lava covered mountains on a small seat on the lava, have a clear view of the lava flows, and late in the early stages lava flows covered in lava flows on top striker forma

West of the Longgang Shan arteries, the river valley lava lower beds are the continental crust basis (various issue of old stratum), east of the sierra, the river valley lava cover above the small chair mountain time lava, has the obvious multi-times, the later period lava flow cover above the early

In Longgang Shan West of veins, underlying formation is the continental crust of the lava of the valley floor (the old formation), East of the mountains, lava lava on top of the mountain covered in small chairs in the River Valley, with a significant number of period, later lava flows cover above th

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