Upon this, I began to consider with myself what innumerable multitudes of people lay confused together under the pavement of that ancient cathedral.
看到这个情景,我暗自思忖,在这座古老教堂甬道下面混埋着何等众多的人呀.
这里what是引导的一个感叹句吗?如果是的话,从句主语是innumerable multitudes of people ,谓语是lay ,主语补足语是confused,从句应该不缺成分吧,为什么用what呢?